M2 Carbines are real bullet hoses; I'll be they run at over 1000rpm. Do you own an ammo factory? I would love to have a full-auto anything, but in practical terms, you can effectively hit targets as well with semi-auto fire. That's a lame reply to, "But I want it", I know.
Selling your M1A1 would get you half way to a nice M1 and the conversion.