Ammo Spotlight: .404 Jeffery / 10,75 x 73mm

By Pierre van der Walt

Cartridge History

Generally known and popular under its British designation, this cartridge is also known in Germany as the 10,75x73mm. Although the cartridge is associated with the British gunmaking trade, the United States pioneered the .423″ bore with the little .44 Henry cartridge of 1873 and then abandoned the calibre. Things then went quiet on the .423″ bore front until the Austrian introduction of the 10,75x57mm Mannlicher-Schönauer in 1900; a cartridge that did not go far.

 

The British eventually popularised the .423″ bore when the famous William Jackman Jeffery Company introduced the .404 Jeffery in 1905. I know that some readers may have known this all along, but also that most readers will immediately sit upright and say: ‘Wrong! It was 1909!’

 

I first became aware of 1905 as the date of the .404’s birth when I was shown a photograph of an unusual cartridge. It all started when the South African collector Petr Skrela obtained a sample of a .450/400×3″ from George Black in Bloemfontein. The cartridge’s rim had been turned off to modify it to rimless, bolt action configuration. It turned out that the rifle for which the cartridge had been made was a magnum length bolt action Rigby; which action size Rigby started using in 1904 with Rigby rifle, serial number 2345. The question arose as to why Rigby had taken this unusual step.

 

The answer is; to compete with the .404 Jeffery, as Rigby did not have a competitive rimless bolt action cartridge at the time. To support this statement I need to backtrack a little. Jeffery had a specific method of referring to cartridges in his catalogues.

 

For example, even by 1910 he referred to the .450 No.2 as: ‘The New 1903 Model .450 No.2 Cordite Express Cartridge. On page 55 of the same 1910 catalogue he refers to the .404 as: ‘The New .404 Rifle, 1905 Model, Rimless Cartridge’. This was an early pointer to the correct birth date of the .404 Jeffery and the absence of a competitive cartridge which prompted Rigby’s behaviour.

More proof that the .404 Jeffery came about before 1909 comes from a letter from Burma, dated 31 July 1907, written by one Percy Smith, congratulating Jeffery on a delightful rifle. This letter can also be found in the Jeffery catalogue and is definite proof that rifles had been ordered, built, shipped to Burma, used and reported back on by 1907.

 

The final nail in the 1909 coffin however comes from a drawing named ‘Tracing 24’ dated 18 October 1905 depicting the .404 cartridge. Subsequently two other .404 drawings from 1907 (Kynoch AQ12/24) and 1908 (Eley 158) respectively have been found. There you have it!

 

Jeffery did not retain the .404 as a proprietary cartridge as many of its opposition did with cartridges they introduced. All gunmakers could chamber rifles for this cartridge, and most did, which naturally resulted in a fair degree of popularity and a hell of a lot of barrel dimension inconsistency.

 

About the .404’s popularity John Taylor wrote: ‘I can say at once that it is one of the most popular and most widely-used calibres throughout the big game hunting world. Altho I have only mentioned two firm’s names in connection with it, most gunsmiths, including the Germans, listed rifles of this calibre in their catalogues – which speaks for itself.’

 

The territories now known as Kenya, Tanzania, Zambia and Zimbabwe adopted the .404 Jeffery as an official game department standard issue chambering. The cartridge saw tremendous service in this role, acquitting itself magnificently. One can actually stop at that as it ends all arguments.

The hands and the 3½” long .404 Jeffery cartridge give perspective on a hippo’s thick skin.

Due to its base and rim diameter being unusual in the US, the cartridge lost popularity after World War II. The Americans could at the time still not unglue themselves from their limiting preoccupation with .30-06 and .375 cases, as the once mighty British sporting ammunition industry gradually collapsed and big bore ammunition production eventually terminated. Fortunately sufficient stocks of ammunition floated around until 1963 when Dynamit-Nobel commenced production again. This availability of cases kept the .404 going while other British cartridges faltered.

 

Several cartridge case manufacturers such as Bell, Hornady, Norma and Bertram eventually began manufacturing .404 Jeffery cases, and a wide range of ammunition can now once again be had. The long and the short of all this is that the case and cartridge were revived.

 

America eventually discovered the .404 case. Dakota Arms lead the way when Don Allen based most of the cartridges in his proprietary line-up on it. Then John Lazzeroni modified it to serve as a basis for some of his designs. Just before the turn of the century a really big name in the cartridge world also came under the .404 Jeffery case’s spell. Remington based its Ultra Mag and Short Ultra Mag cartridge ranges on it; albeit slightly shortened and with marginally rebated rim. Around the turn of the century Rick Jamison and other Americans began using it as a basis for their wildcats, commercial and proprietary cartridges in pursuit of the short-fat benchrest philosophy.

 

As a result of the US awakening to it, this sensible big bore case configuration now at least enjoys a new surge of popularity. One can only hope that the Yanks will discover the .404 cartridge itself as well. The .404 Jeffery is still very much in business in Africa where it has enjoyed uninterrupted adulation for over a hundred years and it is one of my favourites.

 

It took a while before the 6.5 Creedmoor captured the imagination of the American shooting fraternity, but when the 6,5mm penny finally dropped, it did so big time. Today the 6.5 Creedmoor is the best-selling long-range, match cartridge on the planet.

 

Characteristics

The first thing to come to grips with regarding the .404 Jeffery is that its groove diameter is .424″ and not .404″. At .412″ not even its bore diameter is .404″. Where the .404 designation comes from cannot even be guessed at, but I assume it has something to do with the .303. Fact is that it is of larger calibre than the famous .416 Rigby and not every hunter is aware of that.

 

In original cordite configuration the cartridge launched a 400-grain bullet at 2,125 fps from 28″ proof barrels. In actual hunting rifle configuration that probably meant around 2,050 fps. Yet it worked. Unlike humans that grow softer with each generation, African animals seem to grow tougher, because this moderate velocity load proved immensely effective in Africa at the time, whereas modern hunters scorn 2,125 fps of muzzle velocity in bolt action cartridges. Although Taylor mentions a number of reported instances of bullet failure (solids), he concludes that ‘I cannot see that the .404 would have become so popular if its slugs 

habitually behaved so badly.’ I think Taylor was just filling the page here like he did on occasion, as he was not so accommodating when he discussed the metric 10,75x68mm Mauser. At 2,125 fps even 4th Generation (full metal jacketed) solids fail more or less equally often or equally rarely in most large bores. Today there are excellent bullets for the .404 on the market and the modern hunter can rest assured that if he loads up with any quality bullet for this cartridge, he will be well equipped.

 

It was also available in 300-grain bullet configuration. Velocity with these hovered around 2,625 fps in proof barrels and around 2,550 fps in hunting rifles. As expected this pushed Green-Band velocity parameters and problems did occur with the original 4th Generation (jacketed soft point) 300-grain HV factory load, due to incorrect short range application, but none of the modern .404 bullets seem to suffer from this shortcoming; American bonded core bullets in particular. At a maximum average pressure of 52,938 psi (360 MPa) crusher, measured in terms of the CIP protocol, the .404 Jeffery’s prescribed pressures are moderate. It was a good idea in the days of heat sensitive Cordite, and it remains a good idea for dangerous game cartridges to this day, but it is not in line with modern trends. We must perhaps all sit down and develop reasonable pressures for modern propellants in classic cartridges. There are modern propellants that perform remarkably consistently despite surprising changes in the temperature and humidity. Examples are those propellants manufactured by Australian Defence Industries and distributed in the USA under the Hodgdon Extreme banner. It is better to consider most other propellants reasonably heat resistant, but not heat impervious. One should therefore not overdo any attempt at raising modern pressure specifications. Although the basic case has become sought after for its base and head dimensions, the shoulder and neck design of the .404 Jeffery case is antiquated. Its body is reasonably straight, but its neck is 147% of a calibre long and at 8º 30′ 32″ its shoulder angle is very shallow by modern standards. The long neck exhibits excellent bullet retention characteristics, but it could have been shorter and still performed the same.

 

The case can also be evaluated from another perspective. Firstly, it provides all the capacity needed to launch a 400-grain bullet at 2,300 fps from a 24″ (610mm) barrel, while maintaining moderate pressures. Secondly, this cartridge, with its Apollo rocket shape and absence of a belt, feeds like a hot knife through butter: much smoother and better than the various .416’s. Finally, does it not compromise magazine capacity to the extent the .416 Rigby and Weatherby Magnums do. During its heyday the .404 Jeffery was the large bore backbone of African hunting.

 

Much as the 9,3x62mm Mauser was the transition bore mainstay. These two cartridges attained their revered status because they worked so well. Field performance, much more than looks or purist technical requirements, is what counts when evaluating a cartridge. The .404 Jeffery is still delivering the goods consistently after a hundred and five years on the beat. That is what matters.

Performance Summary

Bullet Weight Velocity   Threshold Kinetic Energy Taylor KO Recoil 8lb Rifle
400-gr 2,375 fps  5,011 ft/lb  57.4  58.2 ft/lb
350-gr 2,525 fps  4,956 ft/lb 53.4 53.5 ft/lb
300-gr 2,700 fps 4,857 ft/lb 48.9 47.5 ft/lb
230-gr 2,975 fps 4,521 ft/lb 41.3 38.0 ft/lb
Averaged CSM  4,84 kg / 10.66 lb

Performance

The .404 was designed as a short-range cartridge for massive animals. So applied it shines on eland, giraffe, buffalo, hippo, rhino and elephant. On lion I prefer magnum (2,600fps – 3,00fps) velocity cartridges and the .404 Jeffery will do that with 300-grain bullets. My preference should not be interpreted as meaning that lower velocity combinations do not work on lion. They do. I just have my own preference based on my own reasons, but any bullet that expands quickly and massively yet holds together is decent cat medicine.

 

With a 400-grain round nose bullet loaded to 2,350 fps, the .404 Jeffery’s Green-Band stretches to about 85 yards, and with a spitzer to ±100 yards. Loaded to 2,600 fps, the 350-grain round nose bullet’s Green-Band extends to 160 yards, and the spitzer’s

to 225 yards. That more than suffices for any big and dangerous game hunting and any person who finds himself in need of longer range capability should engage in a lot of sharpening up of his field craft.

 

By large bore standards the .404 offers moderate recoil, smooth feeding and 4,700 ft/lb of kinetic energy. There are more specialised elephant stoppers which generate in excess of 5,000 ft/lb of energy, but there are few cartridges as versatile and easy to use as the .404 Jeffery. There is no visible difference between it and the .416 Rigby insofar as killing is concerned, but recorded statistics favour the .404 over the .416. Neither of course exhibits Taylor’s ‘paralyzing .375 effect from which nothing rises.’ The theory is that it does not penetrate as deep as the .416 Rigby. I have not conducted any statistically sound penetration comparisons, but in reality both cartridges offer all the penetration ever needed and any difference is unrelated to field requirements or results.

 

Much is always made about sectional density of a bullet. The popular conception being that the higher the sectional density, the better a bullet’s terminal stability. Generally sectional density exceeding .300 is considered excellent. A 400-grain .423″bullet has a sectional density of .319, while a similar .416 bullet has a sectional density of .330. Both fall in the excellent category.

The late Steve Lunceford on the left, and the author holding his .404 built on a double square bridge Mauser action. Steve ended the crop-raiding days of this big hippo bull near the confluence of the Limpopo and Magalakwena rivers. Author was there for the ride. Steve sadly died in an aircraft crash in 2011.

However, the popular sectional density perception is not supported by science. It should not be rejected, but it has more to do with weight retention than pure sectional density.

 

We have the right idea, we are just tagging it to the wrong definition. We all know that the longer a bullet is, the faster it must spin to remain stable in air. That does not change during the terminal phase, except that an animal’s body is at least 900 times denser than air. It is common knowledge that the denser the medium through which a bullet travels, the faster it must rotate to remain stable and head on.

 

Given the same mass and twist, a solid .423″ bullet (being shorter and having a lower sectional density than a .416″ bullet) should therefore be more stable than a .416’s during the terminal phase! It is also easier to bend a 6″ rod of a given diameter and material than a 3″ one. So, the longer a bullet is (all else being equal) the more prone it is to bending and losing terminal direction. That however is a separate discussion.

 

My intention is not to tote the .404 Jeffery as better than the .416’s, but merely to show that a great number of considerations used by hunters to pick one cartridge over the other are not particularly scientific, but merely the result of attempts at rationalization or susceptibility to propaganda. To understand terminal stability and penetration better, readers are advised to study the most authoritative publication ever on penetration, namely the book Bullet Penetration – Modelling the Dynamics and Incapacitation Resulting from Wound Trauma by Duncan MacPherson.

 

According to CIP specifications the .404 Jeffery is a tad shorter than the .375 H&H Magnum and countless standard length Mauser actions have been successfully converted to handle the .404, by stretching the magazine and doing some work on the rails and ramp. If you load the .404 to standard magnum length this  is not a problem, but a good case can be made for rather mating it to stretched actions.

Optics and Sighting

My .404 Jeffery is not scoped and until my eyesight began showing signs of ageing I believed that a dangerous game rifle should not really be scoped. That view is changing as quickly as my ability to see the front sight well.

 

My favourite iron sight on such a rifle looks like hell, but works extremely well. It consists of a pillar (Patridge) front sight and a large hole ghost ring rear sight on the bridge. Unlike an express sight it does not block the bottom half of the target, which I find increasingly bothersome as my three dimensional perception across the length of a rifle deteriorates. It offers virtual total visual perspective even for ageing eyes. The distance from bridge to front sight is about twice the distance from traditional rear sight to front sight and a lot of parallax is eliminated. It is fast and effective and it does not bother ageing eyes.

 

I admit to now finding low magnification, wide angle, wide field of view, large exit pupil, long eye relief riflescopes quite effective and with that bit of practice you need when dangerous game hunting, one can actually use a riflescope quite effectively. I have also fallen for electronic reflex sights.

 

For non dangerous game hunting a 1.5-5x, 2-6x or 2-7x riflescope with long (3.75″+) eye relief all work well on the .404. For dangerous game hunting the best option is a 1.1-4x and second best a 1.25-4x. Since the recoil of the Jeffery is not that bad, riflescopes generally last on these guns.

Collecting grass to hang over the lion bait so that the vultures do not get hold of the meat first.

With a riflescope the almost perfect zero is about 90 yards using a 400-gr round nose. It offers a 0.2″ point blank range from about 37-100 yards. Very good for bush hunting. Even at 150 yards it is still within 2.3″ of line of sight, but I have grown so accustomed to my 75-yard zero that I personally do not deviate from it any more.

 

Handloading

If you load the .404 Jeffery to the CIP specified 3.53″ (89,66mm), a 400-grain Barnes RN solid is seated about 0.74″ (18,8mm) deep into the case, and a Woodleigh 400-grain RN solid about 0.654″ (16,7mm), while calibre is only 0.423″ (10,74mm). Nothing (except magazine length and/or leade) compels anybody to compromise the .404 Jeffery’s combustion space by seating the bullet deeper than a calibre, just to conform to CIP overall cartridge length specs. Particularly because cartridge overall length is changed by handloaders for all sorts of reasons, including accuracy. You don’t have to stick to crimping grooves either, especially if you use a Lee factory crimp die sensibly. Changing overall cartridge length affects pressures and should not be engaged in by the inexperienced.

Actual Case Capacities

Case  Brand Case Mass Water Capacity
Norma  298.8 gr  113.4 gr
RWS   291.5 gr 114.3 gr

The .404 Jeffery is a natural to seat the bullet one calibre deep only. It compensates for the sloping shoulder and long neck and increases combustion space. If this approach is followed and the chamber leade is generous, the .404 Jeffery becomes longer than the .375 H&H Magnum and then it requires a magnum length action.

 

Modern propellants enable handloaders to increase velocities to around 2,350 fps with 400-grain bullets from long leade 24″ barrels without exceeding the original  pressure specification by much, or without

This custom .404 Jeffery on a Vektor Magnum Mauser action is one of the author’s favourite rifles. In patent applications William Jackman Jeffery did not describe himself as a gunmaker. His company did not manufacture rifles or guns. He purchased them from Birmingham gunmakers and sold these under the WJ Jeffery brand name. That is one of the reasons why he did not maintain proprietary rights to the cartridges introduced via his company.

approaching the higher pressure levels which are accepted as the norm for cartridges of late.

 

If one looks at the various handloading manuals, and also when you punch the dimensional, volumetric and weight data into the better internal ballistic programmes, it becomes obvious that the slower medium burning propellants between Hodgdon’s H-4895 and H-414 provide the best results with the 400-grain bullet. Once the slow burning propellant category is entered into, suitability fast deteriorates. Somchem S-355 and propellants in the IMR-4064 and IMR-4320 class work well in this cartridge.

 

Although a lot of RWS cases still float around, it ceased making .404 ammunition and components around 2000. At this stage Bertram, Horneber, Kynamco and Reed are the best options for cases. I use Norma cases. They offer great consistency.

 

Woodleigh makes the most popular .404 bullets, but Barnes, GS Custom, Rhino, Stewart, Swift and RWS also manufacture good stuff. I use Swift, Rhino and Stewart softs. Rhino bullets are not always the dimensionally most consistent and I find that irritating on the handloading side, but when you put bullet to flesh, they work.

 

When it was active, A-Square also offered .423″ bullets. According to my information A-Square monometal solids were actually conceived and patented by Eric Lutfy of the Thunderbird Cartridge Company in Phoenix, Arizona.

 

To my mind, the day of the round nose solid has come and gone. The new generation of large meplat solids such as the GS Custom and the North Fork have arrived. I don’t use anything else any more.

The one thing to bear in mind when handloading the .404 case is that it is big. It requires a full size press and proper case lubrication, or the cases get stuck in the dies. It is a candidate for premium quality case lubes such as Imperial Sizing Die Wax.

 

Due to the .404’s sloping shoulder, great care must be taken not to set the shoulders back. Fortunately it has a long neck and it is easy to only resize it partially.

 

As with all cartridges intended to be used on dangerous game, full-length resizing of hunting handloads is recommended. Due to the sloping shoulder the cartridge is a smooth feeder and very few problems in this regard are ever encountered on the .404.

 

Despite the fact that the long necks can fairly easily be buckled when crimps are applied, it is easy to handload.

.404 Jeffery / 10,75 x 73mm Load Data Summary

Bullet Weight Propellant Type Min Load Max Load Max Velocity Barrel Length Data Source
400-gr Bullets Accurate  AA-2520 80.0 gr 83.0 gr 2,456 fps www.loaddata.com.
Alliant Rel-15 76.0 gr 80.0 gr 2,379 fps 26.0” A-Square Any Shot You Want. 1996.
Alliant Rel-12 80.0 gr 83.0 gr 2,410 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Hodgdon H-4350 83.0 gr 86.0 gr 2,221 fps 24.0” A-Square Any Shot You Want. 1996.
Mulwex AR-2209 76.0 gr 85.0 gr 2,450 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Mulwex AR-2208 68.0 gr 71.0 gr 2,100 fps 26.0” ADI Handloaders Guide. 5th Ed. 2010.
Mulwex AR-2206 75.0 gr 79.0 gr 2,358 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Norma MRP-2 96.4 gr 2,343 fps Norma Data Center. September 2010.
Norma N-204 89.0 gr 91.0 gr 2,304 fps 24.0” Ladeboken. 6th Ed. 2006.
Norma N-202 76.0 gr 78.0 gr 2,357 fps 24.0” Ladeboken. 6th Ed. 2006.
Norma N-201 71.0 gr 75.0 gr 2,283 fps 24.0” Ladeboken. 6th Ed. 2006.
Rottweil R-907 80.0 gr 84.5 gr 2,362 fps 23.6” RWS Wiederladen Handbuch. 1998.
Rottweil R-903 76.0 gr 81.5 gr 2,346 fps 23.6” RWS Wiederladen Handbuch. 1998.
IMR-4350 84.0 gr 87.0 gr 2,345 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
IMR-4064 76.0 gr 80.0 gr 2,337 fps 26.0” A-Square Any Shot You Want. 1996.
IMR-4895 80.0 gr 83.0 gr 2,420 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
IMR-3031 75.0 gr 79.0 gr 2,350 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Somchem S-365 72.0 gr 80.0 gr 2,270 fps 24.0” Somchem Data Manual. 1997.
Somchem S-355 74.0 gr 78.0 gr 2,333 fps 25.0” Handload. Not pressure tested.
Vectan Tub-7000 78.7 gr 84.9 gr 2,313 fps 26.0” LHS Germany Data Center. August 2010.
Vectan Tub-Sp11 78.7 gr 81.8 gr 2,362 fps 26.0” LHS Germany Data Center. August 2010.
Vectan Tub-5000 79.0 gr 2,361 fps 24.0” Braceras. Manual De Recarga Armas. 2006.
Vectan Tub-Sp7 74.1 gr 80.2 gr 2,329 fps 26.0” LHS Germany Data Center. August 2010.
Vectan Tub-3000 75.0 gr 2,328 fps 24.0” Braceras. Manual De Recarga Armas. 2006.
Vihtavuori VN-160 90.0 gr 2,161 fps 24.0” Ladeboken. 6th Ed. 2006.
Vihtavuori VN-550 82.8 gr 2,323 fps 25.6” Deva Wiederladen. 5th Ed. 2005.
Vihtavuori VN-150 78.0 gr 80.0 gr 2,307 fps 24.0” Ladeboken. 6th Ed. 2006.
Vihtavuori VN-140 74.0 gr 76.0 gr 2,295 fps 24.0” Ladeboken. 6th Ed. 2006.
Vihtavuori VN-135 73.0 gr 75.0 gr 2,292 fps 24.0” Ladeboken. 6th Ed. 2006.
Winchester WW-748 88.0 gr 2,522 fps www.loaddata.com.
350-gr Bullets Accurate AA-2520 89.0 gr 2,602 fps www.loaddata.com.
Alliant Rel-15 86.0 gr 89.0 gr 2,630 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Alliant Rel-12 85.0 gr 88.0 gr 2,570 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2006.
Hodgdon H-4895 83.0 gr 87.0 gr 2,591 fps www.loaddata.com.
IMR-4064 85.0 gr 88.0 gr 2,600 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
IMR-4895 84.0 gr 88.0 gr 2,625 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
IMR-3031 75.0 gr 79.0 gr 2,350 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Mulwex AR-2208 84.0 gr 87.0 gr 2,610 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Mulwex AR-2206 83.0 gr 86.0 gr 2,600 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2006.
Norma N-204 90.0 gr 2,438 fps 25.6” Deva Wiederladen. 5th Ed. 2005.
Rottweil R-907 85.0 gr 89.0 gr 2,510 fps 23.6” RWS Wiederladen Handbuch. 1998.
Rottweil R-903 85.0 gr 89.0 gr 2,510 fps 23.6” RWS Wiederladen Handbuch. 1998.
Somchem S-341 82.0 gr 86.0 gr 2,523 fps 24.0” Handload. Not pressure tested.
Somchem S-355 78.0 gr 82.5 gr 2,450 fps 24.0” Handload. Not pressure tested.
Vectan Tub-7000 82.6 gr 88.7 gr 2,493 fps 26.0” LHS Germany Data Center. August 2010.
Vectan Tub-Sp11 83.3 gr 89.5 gr 2,493 fps 26.0” LHS Germany Data Center. August 2010.
Vectan Tub-5000 81.0 gr 2,525 fps 24.0” Braceras. Manual De Recarga Armas. 2006.
Vectan Tub-Sp7 76.4 gr 82.6 gr 2,559 fps 26.0” LHS Germany Data Center. August 2010.
Vectan Tub-3000 78.0 gr 2,492 fps 24.0” Braceras. Manual De Recarga Armas. 2006.
Vihtavuori VN-150 80.0 gr 2,411 fps 25.6” Deva Wiederladen. 5th Ed. 2005.
Winchester WW-748 87.0 gr 91.0 gr 2,568 fps  www.loaddata.com.
300-gr Bullets Accurate AA-2520 85.0 gr 89.0 gr 2,789 fps  www.loaddata.com.
Alliant Rel-15 87.0 gr 91.0 gr 2,765 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Hodgdon H-4895 85.0 gr 89.0 gr 2,729 fps www.loaddata.com.
IMR-4895 84.0 gr 87.0 gr 2,750 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Mulwex AR-2208 86.0 gr 89.0 gr 2,730 fps 23.6” N Harvey Reloading Manual. 8th Ed. 2005.
Vectan Tub-5000 86.0 gr 2,755 fps 24.0” Braceras. Manual De Recarga Armas. 2006.

 

Bio

Pierre van der Walt grew up on a farm and began hunting from a very young age. He was just ten years old when he took part in his first lion hunt and captured a cub to keep as a pet. During the Angolan War, he served as a combat officer, and subsequently qualified as both a lawyer and a professional hunter. He published his first firearm article in 1992 and has since become Africa’s most prolific outdoor writer. In 2023, he was awarded the John T. Amber Literary Prize by the US publication Gun Digest for an article on the history and evolution of Czech hunting rifles. He has published four books that are internationally recognised as definitive works on hunting cartridges within the African context, and co-authored The Complete Professional Hunter’s Handbook, which is used as the official manual for professional hunter training in South Africa.

What was said about –

 

African Small Game Cartridges

African Small Game Cartridges is the third book in the author’s highly acclaimed series on hunting cartridges for Africa. Just like his previous two books (African Dangerous Game Cartridges and African Medium Game Cartridges), African Small Game Cartridges, is the most comprehensive ever discussion of the cartridges covered.

 

Like the previous books, it is destined to become yet another reference standard, which will serve the international and African hunting, shooting and reloading fraternities for decades. A generous part of African Small Game Cartridges is dedicated to relevant topics such as barrel life, understanding riflescopes, suppressors, and ballistic coefficients.

 

This coffee table quality reference work extends 480 pages with 350 excellent full colour images and countless performance tables of Africa’s 33 currently most popular .172, .224, 6mm, .257 and 6,5mm hunting cartridges. It takes readers on a grand tour of their history, specifica tions, design features, performance and field application, as well as the reloading quirks of each of these cartridges. African Small Game Cartridges provides unequalled data – around 7,200 loads for American, Australian, African, European and Scandinavian propellants.

 

International experts have made the following comments about this book

 

Johan van Wyk (Australia),Editor of SA Hunter magazine

Hunters and shooters are constantly bombarded by marketing onslaughts from all corners, each pretending to be punting the greatest cartridge or item. While progress cannot be halted, we need to sort the wheat from the chaff, especially for the more novice amongst us. With two authoritative books already under his belt, Pierre van der Walt is well qualified to not only steer the inexperienced in the right direction, but to also provide plenty of food for thought for the experienced. I unreservedly give African Small Game Cartridges the thumbs-up. It is well researched and a worthy addition to any shooter’s gunroom.

 

Mats Bergholm (Sweden) Weapon Systems Expert – Swedish Defence Materiel Administration (FMV)

Pierre van der Walt has done it yet again! His first book, African Dangerous Game Cartridges, is the definitive tome about calibers for Africa’s biggest and deadliest. This book, African Small Game Cartridges, Pierre’s third, is nothing short of a masterpiece. It covers the tiniest ‘African’ calibers, but it is as fascinating from a northern European perspective. The calibers presented also cover calibres used for northern European game hunting, from grouse to elk and non-Africa focused hunters world-wide will benefit equally from this book’s overabundance of information. It fits just as well as a coffee table book in a Swedish moose hunting lodge as it does at a game lodge on the banks of the Limpopo River.

 

Ira Larivers (Zimbabwe) Editor African Hunter Magazine

Unequalled! The subject matter in this book fills a gap in Africana and international literature. The fact that it was written by the master of the genre, Pierre van der Walt, makes it essential reading. Apart from crucial calibre choices, he also covers many other important topics. Everything is very well presented. It includes a detailed appraisal of the 33 Africa popular small game cartridges, plus some lesser-known gems such as the .224 African. African Small Game Cartridges offers unprecedented cutting-edge information and a myriad of high-quality photos in a lasting format. Don’t miss out.

Ammo Spotlight: 6.5 Creedmoor

This drawing of the Creedmoor Range depicting the venue and the crowd attending a day of competitive shooting between American and British riflemen appeared in the 6 October 1877 edition of The Illustrated London News. In those days, society did not frown upon firearm activities.

By Pierre van der Walt

Cartridge History

American popularity makes or breaks cartridges and calibres. I have always been amazed at the apparent ignorance of Americans about the world of cartridges beyond the .30-30 Winchester, the .30-06 Springfield, .308 Winchester and the .223 Remington. A typical example is 6,5mm cartridges. Americans overlooked the potential of this calibre and its cartridges for 113 years before the penny finally dropped for them. Although cartridges such as the .264 Winchester Magnum and the 6.5 Remington Magnum had been around since 1959 and 1966 respectively, the 6,5mm calibre just did not gain any US traction.

 

Fortunately, the Americans eventually discovered the existence of some calibres and cartridges beyond the walls of Springfield, Remington and Winchester. This is an excellent development, because for all other American shortcomings, American buying power has been the decisive factor in the survival of the firearm and cartridge industries.

 

The 6.5 Creedmoor is an example. It emanated from a discussion between Hornady’s Dave Emary and High-Power National Champion, Dennis DeMille on the problems experienced by 6mm wildcat users at the 2007 Camp Perry National Matches. They concluded that a modern, SAAMI regulated commercially produced cartridge that was capable of winning National Matches was needed. The 6mm calibre could obviously not achieve that. Emary and his engineering colleague, Joe Thielen, opted to step up from the 6mm to the 6,5mm calibre with its higher ballistic coefficient potential. Their goal was to create a short-action cartridge capable of supersonic velocity out to 1,200 yards while adding the minimum recoil, and they succeeded.

 

The Creedmoor name is steeped in long-range tradition. Let us step back in history to the post American Civil War era. The statistics indicated that Union Army soldiers only hit one Confederate soldier out of every thousand shots fired during the war. This was a great concern and it was decided to establish an organisation dedicated to the improvement of American marksmanship. The organisation, dubbed the National Rifle Association of America (NRA), was established in New York on 16 November 1871. During 1872, the fledgling body succeeded in convincing the New York Legislature to contribute US$ 25,000 to purchase 70 acres (28,3 ha) of farmland from a Mr Creed, for development as a long-distance

Technical Specs

First Regulator SAAMI
Introduced  2007
Country USA
Relative Case Capacity 53.5 gr water (3,474 cc)
Case Trim Length  1.912” (48,57 mm)
Expansion Ratio  7.8
Groove Diameter .2640” (6,71 mm)
Bore Diameter .2560 (6,50 mm)
Groove Details 6 x .0900” (2,29 mm)
CAB-Ratio 71.8
Minimum Barrel Area  0.0536”² (34,58 mm²)
Std Proof Barrel Twist 1:8.0” (1:203 mm)
Max Average Pressure 62,000 psi (427Mpa)
RCBS Shellholder 3

 

Creedmoor 6.5 bullet

rifle range. When a Colonel Shaw, one of the NRA range committee members first saw the piece of land, he said that it reminded him of a moor. So, it became known as Creed’s Moor and later, simply Creedmoor.

 

The Creedmoor range was officially opened on 21 June 1873 and soon hosted historic competitions such as the famous one between the NRA and the Irish Rifle Team (which included the eminent John Rigby) in September 1874.

 It is therefore rather fitting that Emary and Thielen’s dedicated long-range match cartridge, the first commercial rifle cartridge ever specifically conceived and designed for extreme range competition, was dubbed the 6.5 Creedmoor.

 

It took a while before the 6.5 Creedmoor captured the imagination of the American shooting fraternity, but when the 6,5mm penny finally dropped, it did so big time. Today the 6.5 Creedmoor is the best-selling long-range, match cartridge on the planet.

Characteristics

The 6.5 Creedmoor is an indirect sibling of the .308 Winchester. In 1982 Winchester introduced the .307 Winchester cartridge as a rimmed version of its .308 for the Winchester M-94 Big Bore lever action. The concept did not catch on, but around 2007 the Thomson Center company requested Hornady to create a .30 calibre cartridge for its then new Icon bolt action rifle. Hornady’s Dave Emary is said to have modified the .307 Winchester case by thinning its case walls, shortening it and turning it into rimless configuration to create the .30 TCU cartridge. Both the .307 Winchester and .30 TCU have now fallen by the wayside. The 6.5 Creedmoor is said to have been created by necking a .30 TCU cartridge down to 6.5mm by means of a 30° shoulder. I find this a bit strange, as it would have been simpler to use the .308 Winchester case.

 

The 6.5 Creedmoor has 0.37° body taper and a 30° shoulder, as opposed to the .260 Remington’s 0.69° body taper and 20° shoulder. Despite the Creedmoor being 0.115” (2,92mm) shorter than the .260 Remington, these features, combined with thinner case walls resulted in the .260 Remington beating the Creedmoor by just shy of 4% in the water capacity stakes. The 6.5 Creedmoor has the advantage of a 107.6% of calibre neck as opposed to the Remington’s 97.9% neck.

 

This all sounds as if the 6.5 Creedmoor is way ahead of the .260 Remington and in factory format it does indeed lead, but there is a lot that can be done to ‘improve’ the .260 Remington. For example, if both cartridges are loaded to the same overall length (2.825”) and the same pressure level (62,000 psi – 428 MPa), the performance outcomes actually favour the .260 Remington. The margins are so small however that I have come to consider the two cartridges identical performers.

Dave-Emary-Creedmoor-Hornady

Dave Emery has since retired, but he was one of the conceivers of the 6.5 Creedmoor and played a crucial role in its development. Dave was also involved in the design of several other cartridges during his tenure at Hornady Manufacturing.

It is commonly claimed by retweeting gunwiters that the tighter twist of the 6.5 Creedmoor and its ability to stabilize heavier bullets than the .260 Remington is what gives it the edge. That may be so when used across bush-ranges (≤ 150 yards) and when using 156 – 160 grain bullets. Truth is – nobody uses the Creedmoor in that fashion. The Creedmoor is used across extended ranges in both match and hunting application. It is so rare to find any hunter using bullets heavier than 143 grains for any application, that it can effectively be discounted as an advantage or consideration.

 

The CaB-Ratio of the 6.5 Creedmoor is 71.8 and the Expansion Ratio 7.8. That is middle of the road for both features and translates to reasonable barrel life. The Creedmoor’s CIP ‘S’ measurement or gas turbulence point is inside the case neck – even if barely so. If that is indeed beneficial as claimed by some, I find the position too precariously close (0.03” – 0,76mm) to the mouth to render a truly tangible benefit. An aspect that counts in favour of the Creedmoor is that it usually requires less of a given propellant than the .260 Remington for comparable performance. I compiled a VC Comparison table from the load data tables. According to the data used the Remington requires 2.1% more propellant to achieve a 3 fps (0.11%) velocity advantage. The Creedmoor’s conversion of propellant to velocity (Velocity ÷ Charge) ratio is 1.9% better in the example used. All this means that a 6.5 Creedmoor is the more efficient and that Creedmoor barrels should last to around 2,000 shots in competition and 3,000 for hunting use.

Bullet Propellant   260 Rem 6.5 Creedmoor  
Weight   Type Charge  Velocity V/C  Charge Velocity  V/C
160  H-4350 43.0   2538   59.0  40.6 2500 61.6
150 H-4350   42.0 2635 62.7  41.2 2638 64.0
140 H-4350 42.2 2755 65.3 42.3 2731 64.6
130  H-4350 42.7 2816 65.9  43.0 2800 65.1
120 H-4350 46.5 2960 63.7 45.0  3022 67.2
Average    43.3  2741 63.3  42.4 2738 64.5

 

Performance & Application

 

Handload Performance Figures at 100% Bullet Expansion (24.0” Barrel)

Bullet Velocity Muzzle RTP RTP RTP RTP Recoil
Weight  Threshold Energy Muzzle 100 yd 200 yd 300 yd 8 lb Rifle
160-grain 2,575 fps 2,356 ft/lb 35.1 30.7 26.6 23.0 16.4 ft/lb
156-grain 2,625 fps 2,387 ft/lb 35.6 31.6 28.0 24.7 16.6 ft/lb
150-grain 2,700 fps 2,429 ft/lb 36.2  32.0 28.2 24.7 16.9 ft/lb
143-grain 2,775 fps  2,446 ft/lb 36.5 32.0 27.9 24.3 16.9 ft/lb
140-grain 2,800 fps 2,438 ft/lb 36.4 31.7 27.5 23.8  16.9 ft/lb
135-grain  2,850 fps   2,435 ft/lb 36.3   31.6 27.3 23.5 17.0 ft/lb
130-grain 2,900 fps 2,428 ft/lb  36.4 31.1 26.7 22.7 17.1 ft/lb
123-grain   2,950 fps 2,377 ft/lb 35.5 30.1 25.3 21.2 17.4 ft/lb
120-grain 2,975 fps 2,439 ft/lb 36.4 30.7 25.7 21.4 17.6 ft/lb
110-grain  3,125 fps 2,399 ft/lb  35.6 29.1 23.7 19.1 17.6 ft/lb
100-grain 3,225 fps 2,310 ft/lb 34.4  27.2 21.3 16.5 16.3 ft/lb

 Averaged CSM = 5.29 lb (2,40 kg)

The bullets used for the calculation of the RTP (Relative Trauma Potential), and the Green-Band are quality hunting bullets, not extended range, high ballistic coefficient paper punchers. The hunting bullets used, drop below 2,600 fps at the end of the Red-Band, below 2,200 fps at the end of the Green-Band and below 2,000 fps where the Amber-Band ends.

 

The 6.5 Creedmoor is a great extreme range match cartridge, but for hunting it’s just a 350-yard option and can be stretched to 500 yards given a carefully selected bullet. That disregards my half-second time of flight principle. The needs of hunters differ massively from that of the extended range target shooter. The latter is not at all concerned about terminal ballistics. Their concerns are with external ballistics, not terminal ballistics. Sport shooters want to minimize time of flight, achieve the flattest trajectory possible and extend the supersonic velocity of the bullet as far as possible.

 

Whereas the 140-gr hunting bullet used in the tables fall below 2,000 fps at around 475 yards already and goes subsonic around 1,225 yards. A Berger 140-gr Match Hybrid Target bullet will, for example, only do so at around 585 and 1,575 yards respectively, depending on altitude and atmospheric conditions.

 

Hunters are concerned with reliable expansion, bullet integrity, wound channels and venison destruction. It is so that Karamojo (Walter Bell) hunted elephants with a 6,5mm cartridge in days gone by, but let’s be honest; none of us is Karamojo Bell and times have changed. We should use cartridges within more realistic parameters.

 

A realistic approach is that he 6,5mm cartridges are small game cartridges best suited to species weighing up to 330 lb (150 kg) on the hoof.

Handloading

 

Hornady, Peterson, ADG and Lapua are the leading manufactures of cases for the Creedmoor. Hornady’s have standard large rifle primer pockets while Lapua offers both large and small rifle primer pockets.

 

I am not convinced small primer cases indeed deliver better precision than large primer cases, but as far as I’m concerned, that is only relevant for extreme range precision. Even competitive shooters are at odds about the matter. When you investigate this aspect, it becomes obvious that small primer preferring shooters are pushing the Creedmoor beyond specification. So, we are facing the same

The other big name in the development of the 6.5 Creedmoor was Joe Thielen, also of Hornady. Here Joe is with a nice nyala bull he bagged.

situation with the Creedmoor as the 6mm situation that led to its creation! The high pressures generated by pushing the cartridge beyond specification stretch the primer pockets rather quickly. To strengthen the case head and improve case web integrity, Lapua opted to leave more brass in the area by opting for the smaller primer option. I remain a sceptic.

 

What I can confirm is that case volumetric consistency and case neck tension are major contributors to long-range precision. Lapua cases are extremely consistent out of the box and should be case of choice for the precision shooter. To extract the utmost precision from the 6.5 Creedmoor, rigorous case classification of neck wall consistency and water capacity should be applied. That must be followed by dedicated case preparation steps such as primer pocket uniforming, flash hole deburring, neck turning and regular annealing. So are the use of a top-class press, competition dies and loading techniques.

 

The 6.5 Creedmoor works with a variety of slow-burning propellants in the H-4350 to H-4831 bracket with all bullet weights. Vihtavuori is the one company that developed a dedicated 6.5 Creedmoor propellant: N-555. It burns between the two Hodgdon/ADI propellants mention above.

Bullet  Propellant  Min Max Max Barrel Data
Weight  Type Load Load Velocity Length  Source
160-gr Bullet Accurate AA-4350 37.0 39.8 2450 24.0” Hornady Handbook. 9th Ed. 2012
Alliant Rel-15 34.0 37.2 2450 24.0” Hornady Handbook. 2021
Hodgdon H-4350 37.5 40.6 2500 24.0” Hornady Handbook. 2021
HodgdonVarget 33.4 35.2 2400 24.0” Hornady Handbook. 2021
IMR-4350  37.7 40.5 2600 24.0”  Hornady Handbook. 2021
Norma URP 37.0  39.9 2500 24.0” Hornady Handbook. 2021
Norma N-203 33.6 36.7  2450 24.0” Hornady Handbook. 2021
Ramshot BigGame 36.8 40.2 2500 24.0” Hornady Handbook. 2021
Somchem S-385  41.5   44.0  2600 24.0” Handload. Not pressure tested
Somchem S-361  41.5 43.6 2526  24.0” Handload. Not pressure tested
Somchem S-365 39.9 41.8  2600  24.0” Handload. Not pressure tested
Somchem S-355  34.1 36.4 2525  24.0”  Handload. Not pressure tested
Winchester WW-760 40.0 42.9 2550 24.0” Hornady Handbook. 2021
Winchester WW-748 34.4 36.5 2400 24.0”  Hornady Handbook. 2021​

 

Bio

Pierre van der Walt grew up on a farm and began hunting from a very young age. He was just ten years old when he took part in his first lion hunt and captured a cub to keep as a pet. During the Angolan War, he served as a combat officer, and subsequently qualified as both a lawyer and a professional hunter. He published his first firearm article in 1992 and has since become Africa’s most prolific outdoor writer. In 2023, he was awarded the John T. Amber Literary Prize by the US publication Gun Digest for an article on the history and evolution of Czech hunting rifles. He has published four books that are internationally recognised as definitive works on hunting cartridges within the African context, and co-authored The Complete Professional Hunter’s Handbook, which is used as the official manual for professional hunter training in South Africa.

What was said about –

 

African Small Game Cartridges

African Small Game Cartridges is the third book in the author’s highly acclaimed series on hunting cartridges for Africa. Just like his previous two books (African Dangerous Game Cartridges and African Medium Game Cartridges), African Small Game Cartridges, is the most comprehensive ever discussion of the cartridges covered.

 

Like the previous books, it is destined to become yet another reference standard, which will serve the international and African hunting, shooting and reloading fraternities for decades. A generous part of African Small Game Cartridges is dedicated to relevant topics such as barrel life, understanding riflescopes, suppressors, and ballistic coefficients.

 

This coffee table quality reference work extends 480 pages with 350 excellent full colour images and countless performance tables of Africa’s 33 currently most popular .172, .224, 6mm, .257 and 6,5mm hunting cartridges. It takes readers on a grand tour of their history, specifica tions, design features, performance and field application, as well as the reloading quirks of each of these cartridges. African Small Game Cartridges provides unequalled data – around 7,200 loads for American, Australian, African, European and Scandinavian propellants.

 

International experts have made the following comments about this book

 

Johan van Wyk (Australia),Editor of SA Hunter magazine

Hunters and shooters are constantly bombarded by marketing onslaughts from all corners, each pretending to be punting the greatest cartridge or item. While progress cannot be halted, we need to sort the wheat from the chaff, especially for the more novice amongst us. With two authoritative books already under his belt, Pierre van der Walt is well qualified to not only steer the inexperienced in the right direction, but to also provide plenty of food for thought for the experienced. I unreservedly give African Small Game Cartridges the thumbs-up. It is well researched and a worthy addition to any shooter’s gunroom.

 

Mats Bergholm (Sweden) Weapon Systems Expert – Swedish Defence Materiel Administration (FMV)

Pierre van der Walt has done it yet again! His first book, African Dangerous Game Cartridges, is the definitive tome about calibers for Africa’s biggest and deadliest. This book, African Small Game Cartridges, Pierre’s third, is nothing short of a masterpiece. It covers the tiniest ‘African’ calibers, but it is as fascinating from a northern European perspective. The calibers presented also cover calibres used for northern European game hunting, from grouse to elk and non-Africa focused hunters world-wide will benefit equally from this book’s overabundance of information. It fits just as well as a coffee table book in a Swedish moose hunting lodge as it does at a game lodge on the banks of the Limpopo River.

 

Ira Larivers (Zimbabwe) Editor African Hunter Magazine

Unequalled! The subject matter in this book fills a gap in Africana and international literature. The fact that it was written by the master of the genre, Pierre van der Walt, makes it essential reading. Apart from crucial calibre choices, he also covers many other important topics. Everything is very well presented. It includes a detailed appraisal of the 33 Africa popular small game cartridges, plus some lesser-known gems such as the .224 African. African Small Game Cartridges offers unprecedented cutting-edge information and a myriad of high-quality photos in a lasting format. Don’t miss out.

Understanding Riflescope Terminology

By Pierre van der Walt

The Human Eye

The human eye, with its restrictions and abilities, forms an indispensable part of the riflescope as a sighting system. Optical engineers are compelled to take this into consideration when designing a riflescope, thereby adapting it to the human eye.

It is, therefore, important to grasp the fundamental functioning and limitations of the eye in order to understand the workings of a riflescope.

The human eye can roughly be described as a spherical organ with a 25mm diameter. It consists of a transparent section known as the cornea. Behind the cornea one finds an aqueous-filled anterior chamber, and then the iris which surrounds the lens perimeter and also slightly overlaps it. At the back of the eye there is a reasonably large chamber known as the vitreous body. The rear three-quarters of the inside of the eye consists of a layer of light-sensitive receptors known as the retina. Insofar as riflescope use is concerned, the most important sections of the eye are the cornea, lens and the retina.

Light is necessary for sight. Light rays reflected by any object pass through the cornea and then through the lens to focus on the retina. The image on the retina is then transmitted through the optic nerve to the brain where awareness of the image takes place. The amount of light that can penetrate the eye is controlled by the diameter of the pupil. Pupil diameter is controlled by the involuntary muscles of the iris. In bad light the pupil enlarges and in good light it contracts.

The maximum diameter to which the pupil can expand is about 0.275” (7mm), and then only in pitch darkness. As soon as light passes through the pupil the lens (which has a biconvex shape) is refracted. The refraction focuses the light rays on the retina.

Aberration

Once light rays have passed through the scope lens and having been refracted by the lens glass, it moves through the vitreous body and focuses the image on the eye’s retina. The best focus occurs on a point which is in line with the visual axis of the eye. This point is referred to as the fovea. The focus at other areas of the retina is not as crisp as at the fovea, mainly because of the angle with which the incoming light rays fall on the retina and the imperfect focal points thereof. Light refracted by having passed through a convex lens furnishes a poor image at high magnification. This occurs because the light rays pass through the lens at different points and a complete image does not form at exactly the same horizontal distance from the lens. The centre of the lens has the longest focal length. The focal lengths of surrounding lens areas shorten in direct relation to the curves of the surrounding lens surface. This problematic phenomenon is known as aberration.

Several different types of aberration exist, but are not of any importance for purposes hereof. Chester Moore Hall (1703 – 1771) solved the problem created by aberration by combining crown glass (glass not containing lead or iron) and flint glass (which has different refracting indexes) in a single lens assembly consisting of a convex crown grass lens and a concave flint glass. This enabled him to focus the rays of white light on a single focal point with virtually no separation of the different rays which make up white light.

Ballistic Turrets

These are turrets on riflescopes that offer multiple zero options. In other words, the hunter can zero across various known distances. Say at 100 yards, 200 yards and 350 yards, he can simply dial the range in and shoot with less or no holdover depending on the exact range to the target.

Erector & Field Lenses

One of the most important differences between astronomical and riflescopes is that the latter sports erector lenses in order to furnish an upright image.

Apart from objective, ocular and erector lenses, modern riflescopes also contain field lenses. These lenses influence the route that light rays take through a riflescope and determine the field of view.

Light rays passing through the objective lens group are bent by the convex shape, thereby resulting in an inverted image. Because this group consists of different types of glass, aberrations are corrected and all light rays focus at the same point.

The light then passes through the erector group which turns the image upright. The erector lenses once again have a focal point where the image is in perfect focus. From here the light passes through the ocular lens group into the eye.

In order to have any use as a sight, a riflescope must have sighting mechanism. In modern riflescopes it is the reticules or crosshairs, dot, or whatever reference points has been used.

The reticules must at all times be clearly visible to the shot. There are only two places inside a riflescope where a sharply focused image of the target at all times exists and those are the focal points of the objective and erector lens groups. These focal points are the only places where reticules can be installed in such a manner that both target and reticules are well focused and appear as clear images. Once the light has passed through all the riflescope lenses it reaches a point where the shot can see everything that has been reflected on the objective lens. This point is at the focal length of the ocular lens group, and the distance between this point and the ocular lens group is known as eye relief. Theoretically, this means that there is only one critical point behind a riflescope where a shot can place his eye and see a complete and clear image. In practice, aberration comes to the aid of the shot in this regard because all the light rays exiting from the ocular lens do not have the exact focal length. It is possible to move the eye slightly to the front or the rear of the focal plane and still see a satisfying image. This contributes to fast eye alignment and reduces aiming time, both of which are very important to the hunter.

Eye Relief

Eye relief is the distance at which you can see the full image view through the scope and determines how far behind the riflescope’s ocular (rear) lens the hunter will place his eye for optimum visibility. If you move your eye nearer or further back from the objective (rear) lens, the field of view begins to constrict. Insufficient (short) eye relief will force the hunter to hold his eye close to the riflescope and he can then be hurt when recoil slams the riflescope back into his face. Long eye relief enables the hunter to safely fire hard-recoiling riflescopes without risk of injury. Eye relief varies as magnification on a riflescope is adjusted. The higher one cranks the magnification up, the shorter the eye relief becomes.

The average eye relief for centerfire caliber riflescopes is about 3” (75mm). Riflescopes designed for big bore rifles normally have eye relief varying between 3.5” – 5” (90 – 127mm), and rimfire rifle riflescopes have only 2” (50mm).

Exit Pupil

The extent to which the light rays that fall on a riflescope’s objective lens can be concentrated depends on riflescope magnification, because the riflescope’s exit pupil is determined by dividing the objective lens diameter by the magnification of the riflescope.

A riflescope with a 4x magnification and an objective lens diameter of 40mm has a 10mm exit pupil (40 ÷ 4 = 10mm). In order to fully utilize a riflescope’s objective lens diameter, its resolving power must be sufficient to create an exit pupil with the exact diameter of the human pupil under the prevailing light conditions. To illustrate: A riflescope with a 40mm objective lens requires 7x – 8x magnification to fully utilize the 40mm of lens diameter, because in early morning and late afternoon light the human pupil has a diameter of 0.197”-0.236” (5 – 6 mm). For example: (40mm lens ÷ 7x magnification = 5,7mm exit pupil and 40 ÷ 8 = 5mm).
Optical tests conducted by the Americans during the Second World War established that the human eye can contract to ±0.1” (±2,5mm) in bright light. At dusk, with a light intensity of one candlelight (stated as a candela) the human pupil diameter is 0.197” (5mm).

Suppose you are hunting on a very clear day in bright sunshine and will most likely have a pupil diameter of ±.12” (3mm) and intend using a 4x magnification riflescope. The objective lens diameter will only have to be 0.472” (12mm – 3mm exit pupil x 4 magnification = 12mm). If the objective lens diameter is any larger it will pick up reflections and images under these conditions that the human pupil is unable to absorb.
But light conditions vary, and sometimes the light is poor. Under such conditions your pupil will expand to, say 0.236” (6mm). A 12mm objective lens will absorb insufficient light under such conditions to allow optimum vision, and such a riflescope will be useless, the reason being that the eye pupil of 6mm requires a 6mm exit pupil and a 24mm objective lens (6mm pupil diameter x 4 magnification = 24mm objective lens).
It is for the abovementioned reason that no modern riflescope sports a 12mm objective lens diameter. Another reason exists. A larger diameter exit pupil enables a shot to align his eye faster and easier, because his eye does not have to be exactly behind the centre of the riflescope’s ocular lens. The drawback of unused image whilst using large objective lenses is a small price to pay for the added convenience of better vision and ease of alignment.

Very view advantages in optics come free, and the convenience of a large exit pupil on a riflescope holds the disadvantage of parallax. More about that later.

Field of View

If a hunter holds his eye at the correct eye relief distance from the ocular lens, a cone of sight stretches from the eye pupil to the rim of the ocular lens. This cone forms an angle stretching from the lens rim on the one to the eye and back to the opposite side of the lens rim. This angle is the maximum angle that can be seen through the particular riflescope and is known as the field of view. Suppose a riflescope with a 6x magnification has a field of view of 24°. The visible field at 100 metres will be approximately 37 metres. Because this distance is magnified 6x (reduced) by the particular riflescope, one must divide the distance (37 metres) by 6x. The actual field of view at 100m then is 6,16m (20.2ft). Although it sounds logical to express a riflescope’s field of view in degrees, valid for all distances, most manufacturers express the field of view as one distance at another, for example, 12,8 metres at 100 metres. This system is more concrete and easier to grasp. It means that the shot will see an area of 12,8 m diameter at a distance of 100 metres. At 50 metres he will see 6,4m (half) and at 200 metres 25,6 metres (double).

A riflescope’s field of vision can be widened in three ways:

  • The first is to reduce eye relief. The problem created by this method is that the aiming eye must be held to near to the ocular bell. Recoil can then cause injury when the scope is slammed into the shooter’s face.
  • Another approach is to reduce magnification.
  • The third and easiest solution is to simply increase ocular lens (rear lens) diameter.

Focal Plane & Reticule Position

Where reticules are placed in a riflescope affects the way in which they are perceived by the hunter. A reticule placed in front of the erector assembly (first focal plane) remains in the same visual proportion to the target across the riflescope’s entire range of magnification. The hunter will perceive this as a change in reticule thickness with changes in magnification. In reality the reticules are actually in proportion to the target. It is a system often found on European riflescopes and is not particularly liked in Africa and America, but provides good range-finding capability.

Reticules placed behind the erector assembly (second focal plane) will always stay the same size.

Fixed Power Riflescopes

Fixed power riflescopes are becoming increasingly scarcer as they do not offer the convenience of varying the magnification to suit the size of and distance to the target. Such riflescopes offer a singular magnification, but actually work very well.

Focusing Riflescopes

Not everybody has 20-20 vision and riflescopes must be adjustable to suit different eyes. Riflescope focus adjustment is effected by adjusting the ocular (rear) lens group.

Hunters without refraction errors can use a simple procedure to focus their riflescopes. Relax the eyes by looking at something distant without objects the eye can fix on, such as the cloudless sky. Turn the focus ring on the rear end of the riflescope fully to one side. Then bring the riflescope in position in front of the aiming eye and hold it at the same distance that it will be when shooting. Look THROUGH the riflescope and not at the reticules. If the reticules appear fussy or have a ghost image, adjust the ocular bell until they appear focused when executing the test. Do not keep the riflescope in front of the eye for more than a few seconds otherwise the eye will adapt. Then execute a half-turn on the adjustment ring and repeat the process until at some stage the reticules immediately appear sharp when the riflescope is peeked through.

Lens Coating

It is obvious that the more of the light that falls on the objective (front) lens that makes it out the ocular (rear) lens the better the hunter will see. A riflescope that only allows 60 % of the light that reflects on the objective lens to pass into the eye is not as good as one that allows 97% of such light to pass into the eye.

It is a well-known fact that glass does not allow all light that falls on its surface to come through. Approximately 4% of the light that falls on untreated glass is reflected at each surface where glass and air meet. This figure is equally valid for the surface where light enters glass than for the surface where it exits from glass. Because riflescopes easily contain ten lenses, 40% or more light can theoretically be lost in the process of passing through it.

The problem of light reflection and loss was largely solved by Professor Olexander Smakula (1900 – 1983) of the German firm Zeiss during the 1930s by coating lens surfaces with a thin layer of refractive fluoride and other chemicals. This process was extremely successful. These days, riflescope lenses are coated with numerous layers of chemicals, and some manufacturers claim light transmission through their riflescopes to be as high as 99%. Bear in mind that different light conditions and different eye conditions and colour-blindness levels cause hunters to experience different coatings differently. Some eyes react well to certain types of coating and others not.

Light Transmission – Relative Brightness of Riflescopes

The prospective riflescope purchaser should avail himself of two other terms – the Relative Brightness and the Twilight Factor of a riflescope. Otherwise he will be misled by the performance claimed for a riflescope in poor light conditions.

For many years most riflescope manufacturers published relative brightness indexes for their riflescopes, thereby propagating that a higher brightness factor meant better twilight performance. Relative brightness as a term bandied about is nothing but the square of the riflescope’s exit pupil diameter. The exit pupil diameter is, of course, the diameter of the light beam which exits from the ocular lens and can be determined by holding the riflescope at arm’s length. The bright spot visible on the ocular lens is the exit pupil. Because the exit pupil is determined by the amount of light which pass through the riflescope, it had incorrectly been accepted as a good method to determine a riflescope’s ability to function effectively in poor light. This is incorrect.

Simply put, the exit pupil of a riflescope can be increased by enlarging the objective lens diameter, as the exit pupil is the objective lens diameter divided by the riflescope’s magnification, i.e. 42mm (1,65″) lens diameter divided by 7x magnification = 6mm (0,236″) exit pupil. The brightness index of a riflescope with a 6mm exit pupil is 6×6 = 36. Another example is a 56mm (2,2″) lens diameter divided by 7x magnification which results in an 8mm (0,315″) and a brightness factor of 8×8 = 64. The latter’s relative brightness is 64 which is better than the 36, because the exit pupil is larger.

The relative brightness of two lenses with the same objective lens diameter will differ if their magnifications differ. For example, divide a 56mm lens by 8 magnification, and you will end up with a 7mm (0,275″) exit pupil. If you divide a 56mm lens diameter by 4X magnification it gives a 14mm (0,551″) exit pupil. The riflescope with the smaller magnification has the largest exit pupil and the square thereof will, naturally, also be the largest. Nobody can blame any hunter being under the impression that riflescopes with low magnification are better suited to low light conditions than high magnification.

The truth is that the pupil of the human eye can only open up to a certain extent: ±0.2” (±5mm) in hunting conditions. At that aperture the eye can, like a camera, only absorb and utilize a certain amount of light, being of 0.2” (5mm) diameter. A large diameter light beam cannot penetrate the pupil. Just like a 4” (100mm) pipe cannot accommodate all the water from an 8” (200mm) pipe in the same time without increasing pressure. Riflescopes cannot increase light’s pressure. So, the relative brightness figure is a useless consideration when evaluating a riflescope intended for twilight use and hunters should not be misled by it.

Light Transmission – Twilight Factor of Riflescopes

A riflescope with a high magnification is better suited to poor light conditions because it shows more detail. This is proved and measured by the so-called twilight factor (TF). The twilight factor is determined by multiplying the objective lens diameter with the riflescope’s magnification and then determining its square root.

Example 1 TF = √ lens diameter x magnification
TF = √ 32 x 4
TF = √ 128
TF = 11,3
Example 2 TF = √ lens diameter x magnification
TF = √ 32 x 8
TF = √ 256
TF = 16

The riflescope in example 2 has a higher twilight factor and is therefore better suited to hunting in poor light. What it all boils down to is that a larger objective lens diameter or a higher magnification are both positive factors in poor light.

 

Objective Lens Diameter

The size or diameter of a riflescopes objective lens is governed by the wave theory of light. Light rays move from one point to another in a wave pattern, like ripples in a pool. This causes the outline of an image to become somewhat hazy, almost as if the object is vibrating.

Because of this vibration it is, practically speaking, virtually impossible to observe an absolute perfect point image of any object through a lens. Each point of an image consists of a spot of light with a diffraction ring surrounding it. This ring is called the Airy disc. The only solution is to increase lens size, thereby admitting a greater area of the wave front and then to concentrate the same tightly for better visual resolution. This can be illustrated by drawing something on a large scale. By reducing its size, certain detail is lost, yet it shows more detail then would have been the case had it initially been drawn on a small scale. In the case of lenses this can only be achieved by using objective lenses with a larger diameter.

In order to use the image reflected on the riflescope’s objective lens, the light must penetrate the eye. The light that penetrates the eye must be concentrated in a beam with a diameter not exceeding normal pupil diameter, that being 0.275” (7mm) in pitch darkness and about 0.197” (5mm) in light suitable for hunting. If this image beam (exit pupil) is larger than the pupil, the eye will be unable to see the whole image reflected on the objective lens.

Parallax

Parallax is normally defined as the apparent displacement of an object relative to another because of a shift in the point from which the object is viewed.

This can be practically illustrated with the same example used to determine the dominant eye of a shot – with minor adaptions. Stretch an arm with the hand in the classical hiking gesture out in front of the head, simultaneously aligning the thumb with an object a few metres away whilst keeping one eye closed. Switch eyes without moving the hand or head at all. The thumb will not be lined up with the object anymore. Yet neither the thumb nor the object has moved. It is just the point or angle of observation that has changed. If the thumb is held against the object the apparent movement, because of different observation points, will be minimal or non- existent.

Parallax is one of those terms that baffle most hunters simply because it sounds complicated. In reality, the aspects regarding parallax that the hunter has to master are few and relatively simple, as it is unnecessary to understand or use any mathematical means.

The existence of parallax in all riflescopes is easily determined. Place a riflescope on a solid rest and aim it at an object about ten metres off. Then move the aiming eye horizontally to and fro behind the scope. The reticules will appear to move relative to the point of aim. Yet it is not the case. Once again it is merely the point of observation that moves.

From this we can deduct that if the aiming eye pupil is not exactly aligned with the centre of the exit pupil of the light rays, an angle is created between the eye’s line of sight and the axis of the light moving through the riflescope. This causes parallax and results in a point of impact differing from the point of aim indicated by the reticules to the off-center aiming eye.

This error is so slight that it can be ignored during short-distance hunting. The effect is more pronounced across longer ranges. A long-range hunter normally has sufficient time to align his eye properly, thereby eliminating parallax. For this reason it is important to choose a riflescope with a small exit pupil for long-distance use. Even though the manufacturer claims it to be parallax-free, it is not parallax-free over all distances. That is why a parallax adjustment feature has been introduced on riflescopes to be used at long range. If hunting distances are short or hunting conditions of such a nature that aiming time will be short, riflescopes with larger exit pupils will offer an advantage.

Although the time parallax and its effect are now understood, it remains necessary to explain the reason for its existence.

At the discussion of erector lenses it was stated that the reticules must be placed at the focal length of these lenses to present a clear image of target and reticules, and to place both on the same visual plane.
We all know that a magnifying glass must be held a specific distance from an object in order to present the clearest image to the eye. In layman’s terms it can be said that the moment the magnifying glass is moved away from that point, the focal length does not coincide with the viewer’s eye and the image blurs. A riflescope has the same effect. Because the reticules cannot be moved around in the scope due to design, it follows that the lenses must be calibrated to form their focal points at the reticule position. This, on the other hand, means that the relevant lens group can only be a specific distance away from the target.

Riflescope manufacturers, therefore, choose an arbitrary distance for the target according to where the lenses are calibrated to have the correct focal length. In riflescopes intended for centerfire hunting rifles this distance normally is 100 metres or 100 yards.

The hunter virtually never finds a target at exactly the distance his riflescope is calibrated for and so the focal point inside the riflescope does not form exactly at the desired point where the reticules are situated. This results in the reticules and the image not being on the same plane. The same phenomenon as with the thumb example occurs when the point of observation is moved. Parallax occurs. The nearer the distance between the target and the relevant lens is to the arbitrary 100 metres, the nearer to the desired point the focal point forms and the smaller parallax becomes. The further beyond 100 metres the target stands the progressively more pronounced parallax again becomes.

Some riflescopes, especially high magnification target and silhouette riflescopes being used over known distances, are fitted with an external adjustment ring on the objective bell or a parallax adjustment knob on the turret. This enables the shot to focus the riflescope for each distance over which the riflescope is used in order to eliminate parallax.

Rangefinding Reticules

These riflescopes were originally developed for the military and originally employed a so-called mil-dot system in terms of which the sniper bracketed his target between the cross on the scope reticule and a series of dots, and then calculated the range to the target. It is quite accurate.

Civilians generally do not take the trouble to master the mil-dot system and a variety of simpler systems have been developed for them. This ranges from bracketing animal bodies between sets of lines to a variety of other systems. The advent of portable laser rangefinders has largely eliminated the need for this kind of system, but it remains popular for some reason.

Resolving Power – Human Eye

The resolving power of the average human eye is about one minute, or a 16th°, which means that a normal and healthy human eye can distinguish an object (say blocks on a chessboard) of about 1” (25,4mm) in diameter at 100 yards. If the chess board is moved further afield, the human eye will find it progressively more difficult to distinguish each square until a point is reached where the chessboard will appear grey.

 

Resolving Power (Magnification) – Riflescopes
The resolving power of a riflescope is the relationship between the riflescope’s magnification and the human eye’s resolving power. A riflescope with a 4x magnification will enable the human eye looking through it to distinguish a square (or any object for that matter) over four times the distance the naked eye is able to. Put differently: Over any given distance such a riflescope will enable the shot to distinguish a square a quarter of the size that the naked eye can. The ability of any riflescope to distinguish an object and its details depends on:

  • The type of glass used;
  • The quality of such glass;
  • The degree to which aberrations have been corrected;
  • The diameter of the objective lens.

As a result of modern technology there is a large number of types of optical glass in existence, each with its own properties. Quality and uniformity of the end product depends on the ability of the manufacturer to maintain batch-to-batch consistency.

Trajectory Compensating Riflescopes

See Ballistic Turrets above. Such riflescopes are specifically designed to change the point of impact according to the distances over which the shooting is done. These riflescopes contain certain distance settings. In other words, it is adjustable for distances like 100m, 200m, 300m and so forth. Such a riflescope is sighted in at say 100m and can then be calibrated to be on target at any of the other distance settings when adjusted.

Variable (Power) Riflescopes

A variable power riflescope offers the hunter a range of enlargements (magnification options). If he hunts at close range or large animals, the hunter can reduce the magnification and, if the animal is small or distant, he can increase the magnification to see the target much more enlarged.

 

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