is a rimless bottlenecked centerfire rifle cartridge designed in 1927 by German gunmaker Wilhelm Brenneke.
[2] It is suitable for hunting medium to large game animals in Africa, Asia, Europe, and North America.
The 9.3×64mm Brenneke was designed as a medium bore big-game cartridge for standard-sized Mauser 98 bolt-action rifles.
For functioning in standard-sized Mauser 98 rifles besides common rechambering alterations, the internal magazine boxes have to be adapted by a competent gunsmith to function properly with 9.3×64mm Brenneke cartridges since the cases are longer and have a larger diameter than the 7.92×57mm Mauser military cartridges.
The widespread availability of standard-size Mauser 98 rifles in central Europe and the fact that the .375 H&H Magnum cartridge and its necked-down version the .300 H&H Magnum with approximately 72.4 mm case length and 91.4 mm (3.60 in) overall length were too long to fit in standard-sized Mauser 98 bolt-action rifles made the shorter 9.3×64mm Brenneke an interesting chambering option for European big-game hunters.
[3] Brenneke introduced the 9.3×64mm Brenneke with a 19.65-gram (303 gr) Torpedo Ideal Geschoss (TIG – Torpedo Ideal projectile) designed for big game and a 17-gram (262 gr) jacketed bullet with lead, bronze or a copper tip for smaller game.
Later a special TIG with a bronze tip and a full metal jacket bullet where added for thick skinned dangerous game.
In 2009, the Russian military developed the semi-armour-piercing 9SN cartridge for the 9.3×64mm Brenneke SVDK variant of the Dragunov sniper rifle.
This cartridge has a 16.6 g (256 gr) pointed boat-tailed FMJ bullet with a steel core and achieves a muzzle velocity of 770 m/s (2520 ft/s).
[4][5] The ballistic performance of the 9.3×64mm Brenneke is similar to the .375 H&H Magnum while being smaller and using less propellant - it has 8% less case capacity, making it a more modern, efficient design.
A rare feature of this German rimless bottlenecked centerfire cartridge design is that it has a slightly rebated rim (P1 - R1 = 0.28 mm).
According to the official Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P.)
pressure limit of 440 MPa, the 9.3×64mm Brenneke cartridge can be handloaded to propel bullets ranging from 10 to 21 g (154 to 324 gr) for all kinds of hunting.
certified and became an officially registered and sanctioned member of the German 64 mm "family" of magnum rifle cartridges.
Due to the large case capacity in relation to the 6.5 mm (.264 inch) calibre bore size the 6.5×63mm Messner Magnum is very harsh on barrels.
This makes this cartridge impractical for most competition shooters who tend to fire a lot of rounds in practice to acquire and maintain expert long-range marksmanship.
Practically there can be some muzzle velocity gained by this method, but the measured results between parent cartridges and their 'improved' wildcat offspring is often marginal.
Because the 9.3×64mm Brenneke offers a pressure-resistant cartridge case that can relatively easily be reloaded with primers, powder and bullets and hence be reused several times, it has become quite popular amongst wildcatters.
The finished case was designed to give similar ballistics to the various .300 magnums while having a usable length neck, and fitting standard Mauser Gewehr 98 sized magazine boxes.