Big Bore Compendium – .500 Jeffery

09aThe 500 Jeffery is misnamed as it was designed in Germany under the name “500 Schuler”. Hostilities between England and Germany during the first world war resulted in British firms calling the cartridge the 500 Jeffery instead, although the two cartridges are one and the same. The European designation for the cartridge is 12.7 x 70 mm.

The 500 Jeffery is an excellent big bore stopping rifle pushing up to a 600 grain bullet at 2400 feet per second with proper reloads. Original ballistic were a 535 grain bullet at 2400 feet per second. Lengthwise penetration on buffalo using a 500 Jeffery is reported by Jaco Marais of South Africa. Similar performance can be obtained from the 505 Gibbs and 500 A-Square.

09bThe 500 Jeffery has a cartridge overall length of 3.45″ which permits it to be built on smaller actions such as standard Mauser 98. Before the reader becomes enthusiastic about rebarreling a surplus model 98 Mauser to 500 Jeffery, there are some difficult problems to consider. First, the 500 Jeffery has a rebated rim, which can lead to feeding problems if the rifle is not properly assembled. A few master rifle makers can get a 500 Jeffery to reliably feed from a staggered magazine. Others will prefer to use a single stack Schuler style magazine for its reliability. The original Schuler rifles used a single stack magazine. Another feeding trick is to use a U-shaped follower rather than a standard L-shaped follower in order for the cartridge to ride as high as possible to avoid the bolt overriding it and closing on an empty chamber. Second, the 500 Jeffery is a fat little cartridge that will require construction of a new magazine box and extensive work to the rails and ramp of the rifle. When these issues are considered, the 500 A-Square on a CZ550 action begins to look like a much more attractive option for the budget-minded. If the reader is seeking a high end rifle in 500 Jeffery, then a true specialist at getting such a rifle to feed should be employed by the project, such as Ryan Breeding or Duane Wiebe in California, Dennis Olson in Plains Montana, or Sterling Davenport in Arizona. B. Searcy & Co., Sigarms, Heym, Reimer Johannsen, Karl-Heinz Ritterbusch and Gottfried Prechtl offer very fine rifles in .500 Jeffery as well.

There has been some confusion about specification for the 500 Jeffery as well. It is essential to be certain that your rifle maker and your ammo maker are working from the same spec- ification. There are reports of Kynoch ammunition not properly fitting the chamber of Heym rifles in this caliber. For the reloader this is not a problem because he will simply obtain a sizing die built to his chamber’s actual dimensions.

Example loads:

Cartridge Powder Primer Bullet Velocity Notes
500 Jeffery 101.0 gr. H4895 F215 570 grain 2303 f.p.s.
105.0 gr. Reloader 15 2291 f.p.s.
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