The 7ÃÂ64mm (also unofficially known as the 7ÃÂ64mm Brenneke, though its designer's name was never officially added as a part of the cartridge name) is a rimless bottlenecked centerfire cartridge developed for hunting. As is customary in European cartridges, the 7 denotes the 7 mm bore diameter and the 64 denotes the case length. The 7ÃÂ64mm is a popular hunting cartridge in Central Europe due to its case head diameter and overall length allowing it to easily be chambered in the standard length actions.
At the start of the 20th century the famous German gun and ammunition designer Wilhelm Brenneke (1865âÂÂ1951) was experimenting with the engineering concept of lengthening and other dimensional changes regarding standard cartridge cases like the M/88 cartridge case, then used by the German military in their Mauser Gewehr 98 rifles, to obtain extra muzzle velocity.
In 1912, Brenneke designed the commercially rather unsuccessful 8ÃÂ64mm S cartridge (again in production since 2001). It was intended as a ballistic upgrade option for the Mauser Gewehr 98 rifles that were standard issue in the German military. The German military chose, however, to stay with their 8ÃÂ57mm IS rifle cartridge avoiding rechambering their service rifles for a cartridge that, due to its more favourable bore area to case volume ratio, would ballistically outperform the .30-06 Springfield cartridge of the United States Army. BrennekeâÂÂs engineering concept was to create new, very powerful (for the era) cartridges by enlarging exterior cartridge case dimensions like overall length and slightly larger case head diameter compared to the German 8ÃÂ57mm IS military cartridge case, coupled with an increase in maximum pressure. The concept was essentially sound, and he persisted in the development of new cartridges along this line.
In 1917 Brenneke necked down his 8ÃÂ64mm S design of 1912 to 7 mm calibre, introduced it as the 7ÃÂ64mm, and achieved major commercial success. The 7ÃÂ64mm offered 10-12% more muzzle velocity than the 7ÃÂ57mm Mauser. This results in a flatter trajectory and better performance at longer range. In the years between World War I and World War II, the 7ÃÂ64mm was often regarded by German hunters as a "miracle cartridge", and dozens of different factory loads were available on the German market. It was so highly regarded that the Nazi German Wehrmacht, during the 1930s, even considered replacing the 8ÃÂ57mm IS in favour of the 7ÃÂ64mm for their snipers. The Wehrmacht decided â just like the German Army had in 1912 â to stay with the 8ÃÂ57mm IS cartridges for their Mauser Karabiner 98ks to keep logistics as simple as possible.
Besides the 7ÃÂ64mm rifle cartridge, Brenneke also designed a rimmed version for break action rifles such as double rifles and combination rifles, as well as for single shot rifles in 1917. The rimmed 7ÃÂ65mmR variant of the cartridge was also immediately a commercial success.
In countries where military service cartridges are banned for civil ownership, the 7ÃÂ64 Brenneke is a successful cartridge for hunting and marksmanship.
The 7ÃÂ64mm has a 4.48 ml (69 grain H<sub>2</sub>O) cartridge case capacity. A sign of the era in which the 7ÃÂ64mm was developed is 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.
7ÃÂ64mm maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).
Americans would define the shoulder angle at alpha/2 â 20.42 degrees. The common rifling twist rate for this cartridge is 220 mm (1 in 8.66 in), 4 grooves, àlands = 6.98 mm, àgrooves = 7.24 mm, land width = 3.70 mm and the primer type is large rifle or large rifle magnum depending on the load.
According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes ÃÂ Feu Portatives) rulings the 7ÃÂ64mm Mauser can handle up to P<sub>max</sub> piezo pressure. In C.I.P. regulated countries every rifle cartridge combination has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that 7ÃÂ64mm Mauser chambered arms in C.I.P. regulated countries were, as of 2014, proof tested at PE piezo pressure.
The SAAMI maximum average pressure (MAP) for this cartridge is piezo pressure.
The American .280 Remington cartridge is probably the closest ballistic twin of the 7ÃÂ64mm. When compared to the 7ÃÂ64mm, the .280 Remington has a slightly lower maximum allowed chamber pressure and as an American 7 mm cartridge has a slightly smaller groove diameter. European 7 mm cartridges all have 7.24 mm (0.285 in) grooves ÃÂ diameter. American 7mm cartridges have 7.21 mm (0.284 in) grooves ÃÂ.
The 7ÃÂ64mm is one of the favoured rifle cartridges in Central Europe, and is offered as a chambering option in every major European hunting rifle manufacturer's product palette. The versatility of the 7ÃÂ64mm for hunting all kinds of European game and the availability of numerous factory loads all attribute to the 7ÃÂ64mm chambering's popularity. Loaded with short, light bullets, it can be used on small European game like fox and geese or medium game such as roe deer and chamois. Loaded with long, heavy bullets, it can be used on big European game like boar, red deer, moose and brown bear. The 7ÃÂ64mm offers very good penetrating ability due to a fast twist rate that enables it to fire long, heavy bullets with a high sectional density. The 7ÃÂ64mm's rimmed sister cartridge, the 7ÃÂ65mmR, is also very popular in Central Europe for the same reasons as the 7ÃÂ64mm. The legal banning of ex-military service cartridges like the .308 Winchester, 7ÃÂ57mm Mauser, 8ÃÂ57mm I, 8ÃÂ57mm IS and the .30-06 Springfield in countries like France and Belgium also promoted acceptance and use of the 7ÃÂ64mm and the 7ÃÂ65mmR.