500 Jeffery or 505 gibbs

IvW said:

The Jeffery has been with us for a very long time, yet there is not a great deal of detailed information available for technical research. In fact, much of it is the same basic data restated over and over in slightly different ways. The Jeffery is not a cartridge utilized by thousands of shooters who wish to share their collective wisdom. Published original data comes predominately from independent sources and frequently in conjunction with the promotion of a rifle, cartridge component or ammunition. Subsequently, working with the .500 Jeffery requires a sense of enterprise...sort of like Star Trek, but without Captain Kirk,
but maybe with a little Spock. The Jeffery's operating pressure by current standards is modest. The round is extremely flexible, predictable and well mannered. In a rifle of modern
manufacture, the Jeffery can be nudged to comfortably outperform the higher pressure 460 Weatherby and keep pace with an even higher pressure .500 ASquare.

The Jeffery, loaded even to 3006 Springfield pressure levels, is able to push a 600 grain bullet to 2,500 fps and generate over 8,100 ftlbs
of kinetic energy. It can just as easily be loaded to reduced pressure levels and made into a spectacular plinker; 350 400 grain cast bullets at 1,400 1,600fps. With the right bullet, and in pursuit of appropriate game, it can be quite flat shooting while hanging on to enormous levels of energy. Relying too much on published data and software simulation results will tend to mask the cartridge's potential.

As a ballistic note, the .500 Jeffery is fairly flat shooting. A Barnes 570 grain TSX can be zeroed at 200 yards and shoot that same distance point blank. Even at 300 yards, bullet drop is only 10" and
the bullet is still moving like a runaway freight train with 4,300 ftlbs
of energy. That is pretty spectacular big game cartridge performance.
.500 Jeffery 570 Grain Barnes TSX

Indices Range
Range yds. 0 50 100 150 200 250 300
Velocity ft./sec. 2500 2384 2271 2162 2055 1952 1852
Energy ft.lbs 7909 7192 6528 5913 5346 4824 4343
Path in. 1.5 1.3 2.6 2.2 0.0 4.3 10.9

Barnes TSX 570 .509 3.700" 133.4 IMR 4350 126.0 CCI 250 2522 8052

Woodleigh PP 600 .510" 3.490" 137.1 H4350 128.0 CCI 250 2468 8117

Click to expand...

Cool ! You use Kynoch or Norma ?

Hoss Delgado said:

Cool ! You use Kynoch or Norma ?

Click to expand...

I load my own, Rhino 570 gr expanders and solids.

IvW said:

I load my own, Rhino 570 gr expanders and solids.

Click to expand...

Nice. Hey , since you're a dedicated .500 man , l got two questions. Is it true that there are some issues about standardization of .500 Jeffery ammo ? Like l heard that rifles regulated for Norma will not chamber Kynoch and vice versa ?
Also , does the rebated rim ever cause feeding issues ? The one .500 Jeffery l fired never had any feeding issues , but it was a SABI made custom rifle

Each is an obviously impressive cartridge. Between the two I'd be inclined to choose the Jeffrey. The Gibbs can actually be loaded to a much higher performance level but you'd not be able to shoot the darn thing. The Jeffrey has a more common bullet diameter going for it and while the case design is not ideal (having been to fit the beast into a standard Mauser), it works.

Hoss Delgado said:

Nice. Hey , since you're a dedicated .500 man , l got two questions. Is it true that there are some issues about standardization of .500 Jeffery ammo ? Like l heard that rifles regulated for Norma will not chamber Kynoch and vice versa ?
Also , does the rebated rim ever cause feeding issues ? The one .500 Jeffery l fired never had any feeding issues , but it was a SABI made custom rifle

Click to expand...

There are actually 3 chamber sizes for the 500 Jeff, if you have the right one you can shoot all three through the rifle, the wrong one will not chamber all rounds.

No feeding issues with the rebated rim if done by a competent gunsmith.

Below is all the info regarding chamber sizes and different ones made by different manufacturers. Sabi now how to build rifles including the 500 Jeff.

CASE FOR CIP ADOPTION OF KYNOCH DRAWING BK82/132,
August 21, 1928, AS DEFINITIVE DIMENSIONAL SPECIFICATION
OF .500 JEFFERY CARTRIDGE FOR INSERTION IN TDCC'S

HISTORICAL BACKGROUND

There has long been argument over the origins of the .500 Jeffery cartridge and in particular whether it was designed by Jeffery, or adopted by him from the 12.7 x 70 Schüler, or whether Schüler adopted Jeffery's design. Whether or not he was the designer of the basic case, documentary evidence seems to point towards Jeffery being the first to market his rifle in this calibre, since the surviving records of the company (now held by Messrs Holland & Holland in London) show the first .500 Jeffery rifle to have been sold in 1927. The first documented reference to the Schuler cartridge is recorded(1) as a letter of 18.11.28 offering it to a customer on New York.

It is a common place error in the literature to describe the two cartridges as identical, but this is clearly not so when the original Kynoch Drawing BK82/ 132, dated August 21, 1928, of the .500 Jeffery is compared with the RWS Drawing M466, dated 18/7/40, of the Schuler .500/ 12.7 x 70. The differences in the shoulder position and shoulder angle are significant, and are highlighted in Kynamco Drawing K98/06.

The difference in the cartridges was brought about by the different rifle and loading systems adopted by Jeffery and Schüler. Schüler always built his rifles on a 98 Standard Action with a vertical magazine and a spring clip which held the cartridge as it left the magazine before the bolt picked up the cartridge and pushed it into the chambers. It relied on the extractor springing over the bullet head and a recess was cut into the chamber face to accept this. This method does not require any assistance from a tapered case or neck to assist it's extraction from the magazine as it just pops up as the bolt moves back and ejects the fired cartridge and is held by the spring clip ready for loading again.

Jeffery on the other hand had all his .500 calibre rifles made on Magnum Mauser Actions and had a stack magazine which meant the cartridge was held under the lip of the magazine box and had to be pushed forward out of the magazine box into the chamber by the bullet face, hence the tapered case and shoulder. angle was reduced to assist its entry into the chamber.

The fundamental difference between the two weapon systems has been forgotten by modern gunmakers and the subtle difference between the cartridges were brought about by the different systems.

The question of the manufacturing provenance of surviving original cartridges is also confusing. No examples are known with a K or KYNOCH headstamp, the only headstamps known (from the pre-WWII era) being an enigmatic ".500" and "x Schuler 500 x GECADO". There is no doubt that the latter is a .500 Schüler, manufactured by G C Dornheirn of Suhl (Gecado), and loaded with 118gr Smokeless NC Flake powder. However, the ".500" examples are known Cordite loaded(2), undoubtedly in Britain by Kynoch; it has long been supposed that all these ".500" h/s examples were also made and loaded by Gecado, but the Cordite loading makes this virtually impossible, since this propellant was not used by German SAA manufacturers.

The most likely explanation is that Jeffery (or Kynoch on his behalf) imported straight (un-necked) formed Schuler cases, quite probably from Gecado. Cordite, due to its stranded form, was invariably loaded into un—necked cases, over-wadded with a glaze board disc of case body inside diameter to retain the strands at the base of the case and the case was then finally necked over the wad for bulleting. This dual use of the basic case probably explains the lack of any complete calibre designation (such as ".500 Schüler" or ".500 Jeffery") in the headstamp; both firms promoted their respective versions as a ".500" – Schüler did not use the metric designation in his promotion of the calibre, this appear to have been adopted by RWS in the early 1940s.

This explains the existence of the Kynoch drawing as a loading drawing for the case giving final external dimensions, and a detailed manufacturing drawing of the bullet, which would have been of Kynoch manufacture; German solid bullets of the era were very thin jacketed and would not have been acceptable to Jeffery or their customers. This also indicates independent design by Jeffery and Schuler and intentional differences in the Jeffery cartridge. Although it may have been expedient (and cheaper) for him to import part finished brass using Schüler's base dimensions from Gecado, the use of a Kynoch bullet and his own sloping shoulder profile was very probably done to intentionally prevent Schuler cartridges being used in Jeffery rifles.

The accompanying photograph shows a comparison of two original Gecado Schüler loads, with the two known headstamps, both NC flake powder loaded, and both with the 47° shoulder angle (as measured on specimens) of the RWS drawing. These are compared with a modern Kynoch (Kynamco) .500 Jeffery (with a nominal 25°, as measured 30° on specimens) and a Romey .500 which has a 68° cone angle as measured on specimens. This and the dimensional correspondence of measured original Schüler specimens to the RWS drawing shows this to have been a copy of the original G C Dornheim drawing, which has disappeared. RWS and Dornheim had a working collaboration from the late 1920s until Dornheim was wholly absorbed by RWS prior to WWII, which would explain the existence of the RWS drawing, showing the intent to continue the manufacture of the Schltiler cartridge by RWS, which was undoubtedly thwarted by the war, since no specimens with the RWS headstamp are known.

COMMERCIAL CONSIDERATIONS

When sportsmen ask their riflemakers for a large bolt action rifle, the 500 Jeffery is always the top of the list. The lore of the calibre has spanned 60 years and is again enjoying a resurgence of popularity. Due to this popularity Kynoch are reproducing the ammunition to the specification and original dimensions of their predecessors, and are now making a further 10,000 rounds of ammunition to satisfy the market. In doing so we have to submit the cartridge to be entered into the CIP tables. This was first done in the early part of this year, but referred back because there was confusion over the dimensions. The historical background and technical considerations with these notes answer these questions. The shooting public do not want a 12.7 x 70 Schüler or a hybrid wildcat - they want a .500 Jeffery, to the original dimensional and ballistic specifications.

From a commercial point of view the 500 Jeffery cartridge to the correct original Kynoch English dimensions will fit the few original Schüler rifles, the original Jeffery rifles and the varying non-standard size chambers found in a few modern rifles made in the last 7 to 8 years. It will also fit and chamber safely in the Wolf "Improved" rifles. So there will not be a problem with the ammunition not fitting rifles in the current marketplace, and there will be no need to recall or alter any rifles, although some owners may like their gunsmith to check this for them.

Chamber reamers and head space gauges to the original Kynoch/Jeffery specifications are available from Arthur Smith, Arms Restoration Services Tel/Fax 01206 272354. Drawings of cartridge and chamber will be sent to all the major reamer manufacturers. Cartridge gauges will be available from Kynamco Limited.
Non—CIP signator countries, e g USA and South Africa are making rifles to the original Jeffery dimensions and have to date taken over 5,000 rounds of ammunition and have ordered a further 10,000 rounds for delivery end 1998.

There has been an enormous amount of mis-information regarding this cartridge. The opportunity has now arisen to the benefit of both manufacturer and private users of the calibre to correct all this and have one definitive specification for this cartridge. With its submission to CIP it will allow owners of both original and new rifles to be confident the ammunition made for this calibre will fit and serve the user as well as the original Jeffery cartridge.

TECHNICAL CONSIDERATIONS

Kynamco Drawing K98/06 gives a detailed overlaid comparison of the shoulder profiles of the .500 Jeffery, from the Kynoch drawing, and the 12.7 x 70 Schuler shoulder is 0.8 mm larger in diameter than the Jeffery case at the mid-point of the Jeffery neck cone. This is known to cause chambering problems in original Jeffery rifles when attempting to feed Schuler dimensioned cases; although the Schüler cartridge may be fired, the bolt in many cases has to be forced to shut, and extraction may be hard.

The same drawing also illustrates the hybrid profile proposed by Romey in 1997. It can be seen that this is much closer to the Schüler than the Jeffery profile, and it is also known that cartridges using this profile give the same hard chambering problems as the Schüler case profile. The Romey proposal is in essence a compromise wildcat cartridge that does not fulfil the requirements for Jeffery chambered rifles, though it may be usable in Schüler rifles. It is however an unnecessary further complication to an already complex problem.

However, K98/06 also demonstrates that the Jeffery profile falls within the Schüler profile except very marginally for a short portion of the neck transition, but, given normal manufacturing tolerances, the Jeffery cartridge will not cause hard chambering problems in a Schuler chambered rifle, and also does not compromise the headspacing of the Schuler rifle, since the front of the Jeffery cone coincides sufficiently well with the front third of the Schuler profile to cause no ignition or safety/pressure problems, as the fireforming expansion that will occur is minimal.

From the technical/dimensional standpoint therefore, it can be seen that the "interchangeability" of these two cartridges is in fact one way; the .500 Jeffery may be readily chambered and safely fired in both Jeffery and Schuler rifle, but the Schuler will not chamber in the Jeffery, particularly in a minimum Jeffery chamber.

It would in many ways be preferable, to demonstrate conclusively the differences and to clarify the many misconceptions about these calibres, if both the Jeffery and the Schuler cartridges were to be adopted into TDCCs under their correct designations and with definitively accurate dimensions from the original respective manufacturer's drawings. However, if it is the CIP's preference only to adopt one of these cartridges due to their similarities, it would seem logical that it should be the Jeffery profile as depicted in Kynoch Drawing BK82/ 132, as it alone may be used safely in both chamberings.

REFERENCES

(1) Techel, H. "Die Btichsenmacherfamilie Schuler in Suhl" Patronensammler-Vereinigung e.V., Sonderdruck Mitteilungblatt 1990
(2) Fleming, W. "British Sporting Rifle Cartridges", Armory Publications, Oceanside CA, ISBN 0—939683-11-3, 1993



Above are scans from the KYNAMCO booklet. I have scanned the cartridges in question in detail for comparison. All shown at 200% scale below. It can be seen that there is a significant difference in the KYNAMCO version, especially the groove thickness:

I have a CZ 550 in 500 Jeffery. I highly recommend sending yours to Wayne at AHR for his CZ #1 Upgrade. It's not that expensive and gives you a Model 70 type 3-pos safety, a single stage match trigger that is wonderful and straighten and fills the bolt.

Well worth it. Both rounds (505 Gibbs and 500 Jeffery) are amazing.

BigBore said:

Actually CZ makes the 550 Magnum in both 500 Jeffery and 505 Gibbs. the 500 Jeffery far out sells the Gibbs. CZ will produce the 505 Gibbs occasionally but they are very slow sellers. The 500 Jeffery moves on an off the shelves at a much faster rate. Also reloading dies for the 500 Jeffery is much more available but you will need a 1" press. Hornady and C&H make the dies. I highly recommend you get a Lee factory crimp die too, you can't rely on a roll crimp on this cartridge. Lee doesn't stock the die but they will custom make you one, a must have. Also the only reliable brass is going to be Norma. A few other companies make it too but I have personally see others have issued with other makes of brass in this caliber. So to be safe stay with Norma.

Click to expand...

Bertram in Australia make really high quality brass for most big bore cartridges. I bought 100 pieces of their 500 Jeffery brass and have never had a problem.

Speaking impartially ; both are exceptionally fine performers in the field . I personally prefer the .505 Gibbs . It does not employ a rebated rim . It’s case capacity is larger . And ( when loaded with 600 grain bullets ) it possesses marginally better sectional density than the .500 Jeffery ( although you are really beginning to clutch at straws here ) .

In your context however , I would recommend the .500 Jeffery . The issue with the .505 Gibbs is that it’s rim diameter is .640 inches . The BRNO ZKK - 602’s bolt head is ONLY JUST large enough to properly accommodate the rim of the .505 Gibbs case . And only a very thin sliver of metal is left . While you shall probably be fine , the .505 Gibbs truly benefits from using actions with larger bolt heads such as the Granite Mountain Arms Magnum Mauser Model 98 actions or the Pattern-14 Enfield actions ( the Pattern-14 Enfield bolt features a left lug that extends beyond the bolt face , thus providing additional metal opposite the extractor which can accommodate the rim diameter of the .505 Gibbs ) .

The .500 Jeffery however , features a rim diameter of .575 inches . This is significantly more manageable for the BRNO ZKK - 602’s bolt head . It also features a more compact ( if fatter ) case .

The 500 Jeff is a more efficient cartridge and reloading components and bullets are more readily availible and for the same performance produces less recoil.

In the right rifle the rebated rim is not an issue.

Professor Mawla said:

Speaking impartially ; both are exceptionally fine performers in the field . I personally prefer the .505 Gibbs . It does not employ a rebated rim . It’s case capacity is larger . And ( when loaded with 600 grain bullets ) it possesses marginally better sectional density than the .500 Jeffery ( although you are really beginning to clutch at straws here ) .

In your context however , I would recommend the .500 Jeffery . The issue with the .505 Gibbs is that it’s rim diameter is .640 inches . The BRNO ZKK - 602’s bolt head is ONLY JUST large enough to properly accommodate the rim of the .505 Gibbs case . And only a very thin sliver of metal is left . While you shall probably be fine , the .505 Gibbs truly benefits from using actions with larger bolt heads such as the Granite Mountain Arms Magnum Mauser Model 98 actions or the Pattern-14 Enfield actions ( the Pattern-14 Enfield bolt features a left lug that extends beyond the bolt face , thus providing additional metal opposite the extractor which can accommodate the rim diameter of the .505 Gibbs ) .

The .500 Jeffery however , features a rim diameter of .575 inches . This is significantly more manageable for the BRNO ZKK - 602’s bolt head . It also features a more compact ( if fatter ) case .

Click to expand...

Great points! That's why I went with the 500 Jeffery. A custom rifle based on a GMA action was out of my price range at the time. I'm very happy with my CZ 550 in 500 Jeffery.

colorado said:

Great points! That's why I went with the 500 Jeffery. A custom rifle based on a GMA action was out of my price range at the time. I'm very happy with my CZ 550 in 500 Jeffery.

View attachment 381939

Click to expand...

@colorado
A magnificent rifle , indeed . Does it hold 3 rounds in the magazine ?

colorado said:

Great points! That's why I went with the 500 Jeffery. A custom rifle based on a GMA action was out of my price range at the time. I'm very happy with my CZ 550 in 500 Jeffery.

View attachment 381939

Click to expand...

I love seeing pics of that rifle. It is beautiful, and in one of the coolest calibers in the world!!

thanks! Can't wait to take it hunting again. Soon, I've had COVID so I'm "prevaccinated"

Yes it holds 3 down. Should be more than enough unless you're culling elephants!

Alright, help me out here...

If .510 projectiles are so common and a .505 Gibbs is able to be pushed harder than a Jeffery and lacks the rebated rim... Why hasn't someone come out with the wildcat of a .510 Gibbs? Curious about this.

Wild cats never make it in the DG arena....
How hard you mant to push a 500 Jeff? I have done close to 2500 fps with 570gr bullets....no pressure signs but trust me it is an awakening experience....

All the old faithfull DG cartridges are good enough as they come....wild cats are meant to be hunted not used to hunt DG with....

Forrest Halley said:

Alright, help me out here...

If .510 projectiles are so common and a .505 Gibbs is able to be pushed harder than a Jeffery and lacks the rebated rim... Why hasn't someone come out with the wildcat of a .510 Gibbs? Curious about this.

Click to expand...

Read an article where GMA did exactly that. Probably just easier getting almost the same results out of the 500J, 500A2, and 510 wells. That .510 field does have a few players.

Forrest Halley said:

Alright, help me out here...

If .510 projectiles are so common and a .505 Gibbs is able to be pushed harder than a Jeffery and lacks the rebated rim... Why hasn't someone come out with the wildcat of a .510 Gibbs? Curious about this.

Click to expand...

Rebated rim has never been an issue in any properly built 500 Jeff rifles..it looks odd but that is where it ends...if it really bothers somebody build a 500 Jeff Improved which does not have the rebated rim....

I have owned 3x 500 Jeffery over 15 years.

1/ Sabi Rifle - I ordered 1 for myself and a friend about 15 years ago, from Sabi Rifles in South Africa, at the time the price was right and I knew these guys would make it feed perfectly, which they did. I am fussy on weight, and through a gift of a Vector Magnum mauser 500 Jeffery action delivered to Sabi, it became heavier than ordered, and a thick barrel out front made the rifle very front heavy which I didnt like, I wanted about 10 1/4lb, and got over 11 1/4lb. Everyone who practice fired this rifle wanted one. I was a huge pleasant boom, and blew up limestome rocks incredibly well. My loads were mild at only 2250 fps with the 535grain Woodleigh, however all Buffalo were hit damn hard. My first shot at game with it, (after the hunter fired his fifth 375H&H), this 500Jeffery stopped a charge of a fast coming Water Buffalo at 11 paces. I sold it for more than I paid while it was still mint, and because I had started hunting open floodplains country requiring longer back up shots, it was heavy, and I needed some funds at the time... My observations on this rifle, 3x staggered in the mag, and it fed fantastic, workmanship by Sabi Rifles was STUNNING, and it fed perfetly with Bertram brass, and Woodleigh softs and FMJs.

2/ Mauser 98 Custom - Many years later in Victoria I shouldered a custom Mauser 500 Jeffery with metal work by a Queensland gunsmith, and stockwork by Gordon Cusens of Tasmania. It feft like a fine 375 or 404, pointed fantastic for me, and I just had to have it.... However I soon found it booted me like hell as the rifle weighed right on 9lb, I love big rifles, but personally I hate sharp heavy recoil. I could not tame, and I tried various reloads... Hunting didnt seem a problem, but in practice 2 shots would smash me. It fed perfect, and pointed great. I was about to add weight in the stock, but sold it becasue along came number 3.

3/ London Guns, Melbourne Australia - This 500 Jeffery rifle was a stunner, right on a perfect weight of 10 1/2lbs for the cartridge, perfect barrel contour, a perfect size 602 size action (backwards safety), and it balanced perfectly also. Awesome engraving, lovely stock, feed was again spot on and I carried it when clients had nice 470s or 500 doubles. However my fine Rigby 416 comes up much better, lighter to carry, and for "me" when guiding a much better cartridge on the longest shots we are sometimes called upon. I found I didnt carry or use it anymore.. probably because of weight and recoil, and again I needed the $$s, so it moved on very fast... before advertising, to a good owner.

Conclusion - I believe 10 and a half pounds is the perfect PH carry weight for a 500 Jeffery, and 11lb would be perfect for a Big Game Rifle Club target user rifle. For me, no elephants here, and I'm not a big frame person, and at 88kg I dont enjoy the cartridge at practice. Plus as I am aging and still cover lots of kilometers on foot, I prefer to carry a 400 caliber rifle that weighs under 10lb loaded. I have learnt that only shot placement will stop a charge, and missing the brain by 3/4" might not stop a charge (an experience with a 465H&H, lucky for the second barrel).

500 Jeffery or 505 Gibbs? - Personally either are fantastic if all rifle dimensions suit the owner, and if ammunition is loaded to suit the capabilities of the owner. Hot loads in big calibers in my thinking are just plain stupid... that can crack a stock, cause an extraction failure, or heavy recoil can cause a miss. In the old days most ammo never usually went as fast as the brochure, and the animals died just the same. Either rifle can be made to balance perfect, so that is most important. I would suggest 11lb for the Gibbs, which WILL kick 10 to 15% more simply because of more powder, for the same velocity.

Bolt Action or Double? - We are all different. Personally I dont like empty. I want 4or5 rounds available, in a cartridge with extreme penetration for Buffalo. But if you chose to hunt Elephant with a bolt rifle, then a 458Lott is great (but a .458 bullet going into a .532 hole doesnt help), (and we've seen a few jam, or slow up feed), the 450 Rigby, the 500 Jeffery, the 505 Gibbs are all stunning cartridges, if in a perfetly fitting and feeding bolt rifle. I wish the 500 Hatari from 18 years ago had evolved properly to gun makers, with full rim, and longer neck, to fix the doubts..

Lets hope we can all get travelling again, to get the powder burning and for the sake of conservation. Be safe.

500 Jeff needs to weight 10 1/2 to 11 1/2 pounds in my opinion..