Although the United States had developed the M2 Carbine, a selective-fire version of the M1 Carbine during WW2, the .30 Carbine cartridge was closer to a pistol round in power, making it more of a submachine gun than an assault rifle. It was also adopted only in very small numbers and issued to few troops (the semi-automatic M1 carbine was produced in a 10-to-1 ratio to the M2), while the AK47 was produced by the millions and was standard-issue to all Soviet troops, as well as those of many other nations. The U.S. was slow to follow suit, insisting on retaining a full-power, 7.62×51mm NATO rifle, the M14 (although this "was" selective fire).