gr (9.50  g ) 2,756 ft/s (840 m/s) 2,472  ft-lbs (3,352  J ) Source: Popenker [ 1 ] [ 2 ] The 7.62x51mm NATO is a rifle cartridge developed in the 1950s as a standard for small arms among NATO countries. Specifications for the 7.62x51mm NATO cartridge are not identical to the commercial