it was made to replace the m1911a1 PISTOL because with special troops(radio operators,tankers,mortar teams,and so on) who could not carry a full size rifle but would have to carry nothing but a m1911a1 that would not be very smart so the m1 carbine was designed but the miilitary dropped the idea when ww2 was going on and issued them as one of the standerd issue rifles each do have there places when the idea was dropped and like I said they made a great choice.