7.62mm UKM

The 7.62mm UKM (7.62 x 57 mm) is a specialized rimless bottlenecked centerfire cartridge developed for long-range rifles. The commercially successful .338 Lapua Magnum cartridge has functioned as the parent case for the 7.62mm UKM, which is essentially a necked-down shortened version of the .338 Lapua Magnum. The .338 cartridge case was used for this since it has the capability to operate with high chamber pressures which, combined with smaller and hence lighter bullets result in high muzzle velocities.

Read more about 7.62mm UKM:  History, Cartridge Dimensions, Additional Information