um..
Not new idea, and making the barrel under 16 inch only makes it a less effective M1 Enforcer but I guess its cute.
Muzzle velocity will drop from around 1900 fps to 1300 to 1500 fps with 110 gr ball ammo. Still an effective fifteen or thirty round tool for home defense. ... Would make nice SBR when the collapse arrives. Choate makes a nice pistol-grip stock for the M1 carbines. I wonder if the gas port has been sized properly, since dwell time will be reduced by shortening the barrel?