The .338 Federal (8.61×51.18mm) is a full power rifle cartridge. It uses the .308 Winchester as a parent cartridge; the .308 case is necked up to accept .33 caliber bullets. It was created by the American company Federal Cartridge, in conjunction with the company Sako.
The .338 Federal began production in 2006.
The .338 Federal, like almost all cartridges derived from the .308 Winchester, is a rimless cartridge, and uses a large rifle primer. The case is necked up to accept a .33 caliber (8.6mm) bullet. The overall length of the cartridge is 2.75 inches.