Colt M16

[Hkmp5sd]

I own a Colt M16A1. I would like to convert it into an M4 (CAR) variation, yet be able to return it to the A1 configuration.

Are the parts interchangable enough that I can simply buy one of the M4 upper recievers and snap it onto my M16A1 lower reciever or would it need to be fitted by a gunsmith?

 

[Ben Swenson]

should be able to just snap the new upper on and swap stocks & buffer tubes.