The 7x64mm (unofficially known as the 7x64 Brenneke) was designed in 1917 by Wilhelm Brenneke (1865-1951) of Germany. The parent case is the 8x64mm S with a narrowed neck to fit a .285 inch bullet on a .313 inch neck. The case is a rimless, bottleneck with a 1:8.66 twist and a large rifle primer. The case length is 2.52 inches with overall length of 3.307 inches and can fit a maximum load of 69 grains.
The ballistic performances based off three grain types for muzzle velocity on the 7x64 Brenneke are 3,000 ft/s (123 gr SP), 2,900 ft/s (154 gr SP), and 2,700 ft/s (174 gr SP.) The 7x64mm was a commercial success after it went onto the public market in 1917 due to its ability to achieve up to 12-percent more muzzle velocity over the 7x57mm with a flatter trajectory and better long range shooting performance.
Hand loading brass is available in a variety of loads for the 7x64 Brenneke. Hornady reloading data states a 154 grain bullet has 2,500 ft/s muzzle velocity with 46.9 grains of IMR-4350 powder, and 2,900 ft/s with 52.9 grains of IMR-4350 powder. The 7x64 has a typical drop-off in trajectory and wound performance at a distance of approximately 235 yards before noticeable down scaling occurs.
