The 6mm Lee Navy (6×60mmSR), also known as the 6mm U.S.N. or .236 Navy, is an obsolete American  rifle cartridge. It was the service cartridge of the United States Navy and Marine Corps from 1895, officially replacing the .45-70 Government round, and was the first small-bore high-velocity smokeless powder cartridge to be adopted by either service. The 6mm Lee Navy was in turn replaced by the .30 Army (.30-40 Krag) cartridge in 1899.