The 5.6×39mm, also known in the U.S. as .220 Russian, is a cartridge developed in the late 1950s for deer hunting in USSR as well as 100 meter running deer competitions. It is a 7.62×39mm cartridge necked down to hold a 5.6 mm bullet. It was later adopted by Finland, and by around 1965 was being produced by SAKO and Lapua. When it was introduced to the United States, Sako, and later Lapua, brass was stamped ".220 Russian". The 7.62x39mm is the parent case for the .220 Russian, .22 PPC, 6mm PPC, 6mm ARC, and the 6.5mm Grendel cartridges.