9.3×64mm Brenneke

The 9.3x64mm Brenneke (also unofficially known as the 9.3 x 64) is a rimless bottlenecked centerfire cartridge developed for big-game hunting. The 9.3 denotes the 9.3 mm bullet diameter and the 64 denotes the 64 mm case length. Using the bullet diameter is unusual in German cartridge designations. Normally the approximate land diameter of the barrel is used for such designations.

The 9.3x64mm Brenneke can be chambered in standard-sized Mauser 98 bolt action rifles. The M 98 bolt actions and magazine boxes of standard military Mauser 98 rifles, however, have to be adapted by a competent gunsmith to function properly with these magnum cartridges since their cases are longer and have a larger diameter than the 8x57mm IS service cartridges.

History
One of the most successful cartridge designs of the famous German gun and ammunition designer Wilhelm Brenneke (1865–1951) was the 9.3x64mm Brenneke. He designed this cartridge de novo (the 9.3x64mm Brenneke has no other cartridge as parent case) and introduced it commercially in 1927. This big-game cartridge is the most powerful cartridge he designed. The 9.3x64mm Brenneke was designed to have the largest possible case capacity without any shape or dimensional drawbacks that would hamper its chambering and perfect functioning in Mauser Gewehr 98 rifles that were then standard issue in the German military.

The widespread availability of standard-size Mauser 98 rifles in central Europe and the fact that the .375 Holland & Holland Magnum cartridge and its necked-down version the .300 Holland & Holland Magnum with approximately 72.4 mm case length were too long to fit in standard-sized Mauser 98 bolt action rifles made the shorter 9.3x64mm Brenneke an interesting chambering option for European big-game hunters.

Brenneke introduced the 9.3x64mm 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. After that Brenneke developed a 19-gram (293 gr) Torpedo Universal Geschoss (TUG – Torpedo Universal projectile) with a lead tip that is still produced.

In 2009, the Russian military developed the semi-armour-piercing 9SN cartridge for the 9.3x64mm Brenneke SVDK variant of the Dragunov sniper rifle. This cartridge has a 16.6 g (256 gr) pointed boat-tailed FMJ bullet with steel core and achieves a muzzle velocity of 770 m/s (2520 ft/s). The 9SN cartridge should be able to defeat body armour at ranges up to 600 metres (660 yd).

The 9.3x64mm Brenneke ballistic performance is on par with the .375 Holland & Holland Magnum while being smaller and using less propellant - it has 8% less case capacity, making it a more modern efficient design.

With the official certification of the 6.5 x 63 Messner Magnum this German 64 mm "family" of magnum rifle cartridges that all share the same basic cartridge case got expanded 71 years later.

The cartridges in this German 64 mm cartridge "family" are, in the order of development:
 * 9.3x64mm Brenneke (1927)
 * 6.5 x 63 Messner Magnum (2002)

Cartridge dimensions
The 9.3x64mm Brenneke has 5.71 ml (88 grains) H2O cartridge case capacity. A rare feature of this German rimless bottlenecked centerfire cartridge design is that it has a slightly rebated rim (P1 - R1 = 0.28 mm). A sign of the era in which the 9.3x64mm Brenneke was developed are the gently sloped shoulders. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles, under extreme conditions.



9.3x64mm Brenneke maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).

Americans would define the shoulder angle at alpha/2 ≈ 17.49 degrees. The common rifling twist rate for this cartridge is 360 mm (1 in 14.17 in), 4 grooves, Ø lands = 9.00 mm, Ø grooves = 9.28 mm, land width = 4.60 mm and the primer type is large rifle magnum.

According to the official with Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P.) guidelines the 9.3x64mm Brenneke case can handle up to 440 MPa (64,000 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers.

The .375 Holland & Holland Magnum cartridge is probably the closest ballistic twin of the 9.3x64mm Brenneke. When compared to the 9.3x64mm Brenneke the .375 Holland & Holland Magnum has a slightly larger calibre and it is a belted cartridge

The 9.3x64mm Brenneke in field use
The 9.3x64mm Brenneke is a powerful cartridge and one that's been highly praised by famed outdoor writer Craig Boddington as easily being equal to, if not better than, the 375 H&H. Like every other big-game cartridge it presents a stout recoil. An appropriate fitting stock and an effective muzzle brake will help to reduce recoil induced problems. An advantage of the short stocky 9.3x64mm Brenneke is that it can be chambered in standard sized bolt-action rifles.

German big-game hunters often use 9.3x64mm Brenneke rifles in Africa for hunting plains game and Big Five game, where British or American hunters would choose the .375 Holland & Holland Magnum or similar cartridges. As a pure civil cartridge it can be used in countries which ban civil use of former or current military ammunition. The 9.3x64mm Brenneke has a good accuracy reputation i.e. it is not hard to develop or find loads that will shoot 1 MoA (0.3 mrad) or better out of decent standard mass-produced rifles.

There are not many factory loads available. After World War II only the 19-gram (293 gr) TUG was produced by the Brenneke Company and later a 18.5-gram (285 gr) round nose and a 16-gram Torpedo Optimal Geschoss (TOG – Torpedeo Optimal projectile) bullet were added to the Brenneke factory load pallet. With these loads the 9.3x64mm Brenneke gained a good reputation amongst German hunters on their big-game safaris.

The German ammunition manufacturer RWS also offers two factory loads. In America A-Square offers the 9.3x64mm Brenneke loaded with 18.5-gram (285 gr) lion load, 18.5-gram (285 gr) dead tough and 18.5-gram (285 gr) monolithic solid bullets.

Due to its good field reputation, efficiency and flexibility, the 9.3x64mm Brenneke is often used by reloaders. They have used this cartridge extensively to create powerful loads by handloading. Whilst staying within the 440 MPa C.I.P. limit a 9.3x64mm Brenneke rifle with a 610 mm (24 in) long barrel and appropriate modern gunpowder can be handloaded to propel bullets ranging from 5.8–20.7 grams (90–320 gr) for all kinds of hunting.

Reloaders realized that bullets with different characteristics can be utilized to produce varying effects on game. They also realized that from 8 mm calibre upwards the rise of sectional density and penetrating capability of practical spin stabilized rifle bullets (bullets up to 5 to 5.5 calibres in length) tends to flatten out.

This means that loaded with light, short and soft-nosed 9.3 mm bullets the 9.3x64mm Brenneke can be used on remarkable small game. Loaded with heavy, long and hard (solid copper) bullets the 9.3x64mm Brenneke offers enough weight and speed-derived power to penetrate heavy and dangerous game. The 9.3x64mm Brenneke is suitable for hunting any game animal on the planet, though certain sub-Saharan Africa countries have a 9.53 mm (.375 in) minimum calibre rule for hunting Big Five game—i.e. leopard, lion, cape buffalo, rhinoceros and elephant. In the growing number of countries where the 9.3x64mm Brenneke can be legally applied, it is used successfully for hunting elephant, making it a flexible safari cartridge.

The 9.3x64mm Brenneke parent case for the 6.5x63mm Messner Magnum
The 9.3x64mm Brenneke case has also functioned as the parent case for the 6.5x63mm Messner Magnum, which is essentially a 6.5 mm (.264 in) necked-down version of the 9.3x64mm Brenneke. The wildcat status of the 6.5x63mm Messner Magnum ended in 2002 when it got C.I.P. certified and became an officially registered and sanctioned member of the German 64 mm "family" of magnum rifle cartridges.

The 6.5x63mm Messner Magnum has 5.42 ml (83.5 grains) water cartridge case capacity.



6.5x63mm Messner Magnum maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).

Americans would define the shoulder angle at alpha/2 = 29 degrees. The common rifling twist rate for this cartridge is 200 mm (1 in 7.87 in), 6 grooves, Ø lands = 6.45 mm, Ø grooves = 6.70 mm, land width = 3.50 mm and the primer type is large rifle magnum.

According to the official C.I.P. guidelines the 6.5x63mm Messner Magnum case can handle up to 440 MPa (64,000 psi) piezo pressure.

The idea behind the 6.5x63mm Messner Magnum was to develop a very powerful 6.5 mm long range hunting cartridge that achieves very high muzzle velocities out of relatively short 600 mm (23.6 in) long rifle barrels. The developer, Mr. Joseph Messner from France, chose the 9.3x64mm Brenneke as parent case, since it offers enough case capacity and a competent gunsmith can relatively easy rechamber a standard Mauser 98 or any other bolt action rifle to accept 9.3x64mm Brenneke based cartridges. Beside the 6.5x63mm Messner Magnum rimless rifle cartridge Mr. Messner also designed a rimmed version for break action rifles of the cartridge called the 6.5x63mm R Messner Magnum.

Due to the large case capacity in relation to the 6.5 mm (.264 inch) calibre bore size the 6.5 x 63 Messner Magnum is very harsh on barrels. It typically wears out a rifle barrel in 500 to 1000 rounds. A lot of thorough barrel cleaning (after every 5 shots) and carefully avoiding long strings of shots help to minimize barrel wear. 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.

The German 6.5×68mm cartridge introduced in 1939 and the American .264 Winchester Magnum cartridge introduced in 1959 are probably the closest ballistic twins of the 6.5x63mm Messner Magnum and both are more widely available to purchase at retail.

.376 Steyr
Another commercial cartridge that uses the 9.3x64mm Brenneke as parent cartridge is the .376 Steyr. This is essentially a shortened 9.3x64mm Brenneke cartridge necked-up to 9.5 mm (.375 in) calibre developed as an evolution of Jeff Cooper's "Super Scout" medium rifle concept, which was in turn an extension of his original scout rifle concept. With a higher felt recoil, the .376 Steyr is the largest practical cartridge for use in a short, lightweight weapon as the Steyr Scout rifle.

Wildcats
Cartridges that are not officially registered with nor sanctioned by C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portative) or its American equivalent, SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) are generally known as wildcats. By blowing out standard factory cases, the wildcatter generally hopes to gain extra muzzle velocity by increasing the case capacity of the factory parent cartridge case by a few percent. 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. Besides changing the shape and internal volume of the parent cartridge case, wildcatters also can change the original calibre. A reason to change the original calibre can be to comply with a minimal permitted calibre or bullet weight for the legal hunting of certain species of game.

Wildcats are not governed by C.I.P. or SAAMI rules so wildcatters can capitalize the achievable high operating pressures. Because the 9.3x64mm 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.

An example of a 9.3x64mm Brenneke-based wildcat is the 8 mm Mázon. This is essentially a 8 mm (.323 in) necked-down version of the 9.3x64mm Brenneke. An example of a 6.5x63mm Messner Magnum-based wildcat is the 8.5 Messner Magnum. This is essentially a 8.5 mm (.338 in) necked-up version of the 6.5x63mm Messner Magnum.