I own only pre-94 Colts and have read from this board and others about various retaining pin hole sizes. Other than the legal problem, could a pre-94 M4 Upper be installed on a post 94 receiver (Match Target, etc.) without retaining pin hole modifications? In other words, would it be a perfect fit? If not, what are the modifications?
Providing the September 1994 firearms legislation is not renewed, I can see a lot of new hybrid Colts being assembled by resourceful citizens.