The M1 Carbine was originally designed to be carried in lieu of sidearms by troops in "support" roles like transportation or artillery units. An awful lot of them ended up on the front lines in Korea. As others have mentioned, they have similar ballistics as a .357 magnum.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.