The M1 Garand uses .30-06 Springfield ammo. In the right hands, it's good enough for any critter in North America, IMHO.
The M1 Carbine uses a .30 caliber carbine round that's good enough for two legged critters at the closer ranges. Someone must have tried it as a handgun round. I wonder what happened?
These Wikipedia links provide the dimensions of the empty cartridge case in millimeters, i.e. diameter and length, IIRC. Somebody correct me if I'm wrong.
P.S. Wikipedia is not a suitable source for any political topic, but for a technical ready reference, it seems OK.