From Wikipedia, the free encyclopedia:
"The 7x64mm (also unofficially known as the 7x64mm Brenneke, though its designers name officially never was added as a part of this cartridge name) is a rimless bottlenecked centerfire cartridge developed for hunting. As is customary in European cartridges the 7 denotes the 7 mm bullet caliber and the 64 denotes the 64 mm (2.52 in) case length. The 7x64mm is a popular hunting cartridge in central Europe and can due to its 84 mm (3.307 in) overall length easily be chambered in standard sized Mauser 98 bolt action rifles.
At the start of the 20th century the famous German gun and ammunition designer Wilhelm Brenneke (1865–1951) was lengthening standard cartridge cases like the M/88 cartridge case, then used by the German military in their Mauser 98 rifles, to obtain extra muzzle velocity.
In 1912 Brenneke designed the commercially rather unsuccessful 8x64mm S cartridge. It was intended as a ballistic upgrade option for the Mauser Gewehr 98 rifles that were then standard issue in the German military. The German military chose however to stick to their 8x57mm IS rifle cartridge avoiding rechambering their service rifles for a cartridge that due to its more favourable bore area to case volume ratio ballistically would outperform the .30-06 Springfield cartridge of the United States Army. Brenneke’s engineering concept to lengthen the 57 mm (2.244 in) long M/88 cartridge case to create new for those days very powerful cartridges was essentially sound and he persisted in the development of new cartridges along this line.
In 1917 Brenneke necked down his 8x64mm S design of 1912 to 7 mm calibre and introduced it as 7x64mm and achieved a major commercial success. The 7x64mm offered compared to the 7x57mm about 10 to 12 % extra muzzle velocity. This results in a flatter trajectory and better performance at longer range. In the years between World War I and World War II the 7x64mm was often regarded by German hunters as a “miracle cartridge” and dozens of different factory loads where available on the German market. It was that highly regarded the German Wehrmacht (Army) during the 1930s even considered replacing the 8x57mm IS in favour for the 7x64mm for their snipers. The Wehrmacht decided - just like the German army in 1912 - to stick to the 8x57mm IS cartridge for their Mauser Karabiner 98k to keep things as simple as possible in their logistical chain.
Beside the 7x64mm rifle cartridge Brenneke also designed a rimmed version for break action rifles of the cartridge in 1917. The rimmed 7x65mm R variant of the cartridge was also immediately a commercial success."
7x64mm. (2009, February 28). In Wikipedia, The Free Encyclopedia. Retrieved 14:52, March 20, 2009, from http://en.wikipedia.org/w/index.php?title=7x64mm&oldid=273945573