U.S. M3 Grease Gun

摘要

I always find it interesting that the M3 SMG, which served in the U.S. armed forces for half a century, is so little known compared to other arms that had much shorter service lives. Designed to replace the expensive Thompson submachine gun (SMG) with one that was lighter and less expensive to produce, the M3 used steel stampings that were welded together for the receiver. Other design features included a firing pin in the bolt, twin guide rods for the recoil springs supported by the bolt, and a cold-swaged barrel. The M3 was not only designed for ease of production, but with tolerances that would allow it to keep operating in sandy, muddy, or dusty conditions. The German MP40 and British Sten SMGs influenced the M3's design. However, unlike those two weapons, the M3 was intended to fire the .45 ACP round, though prototypes chambered for the .30 Carbine round were also built.