Originally Posted by ttpete
It's an extremely underpowered shoulder-fired weapon that was supposed to replace a 1911 .45. It didn't.
The idea being that the average rear echelon troop can make a 100 yard shot with it vs a 45 pistol. Being a light weight carbine, they are more likely to have it with them when it is needed versus handing them a big heavy rifle and expecting them to lug it and their typewriter or tool box around. I bet more enemy soldiers were killed with an M1 Carbine in WWII than with a Colt 45ACP.