It didn't help that the US named everything "M-Number" and gave multiple pieces of equipment the same numbers. Oh, you want an M1? Did you mean the M1 Garand rifle, the completely unrelated M1 carbine rifle, an M1 Thompson gun, an M1 flamethrower, an M1 helmet, or an M1 light tank? Oh, you want an M1 tractor? Cool, which kind?