There are a bunch of stripped camouflaged 870 Super Mags receivers available on Gunbroker, A friend asked me, since he knows I have been fooling with 1100's and 870's for a long time, if you can take the parts out of a 870 Express to build a gun on a SMAG receiver. As I understand it, the parts that are different are those that were changed dimensionally to allow the receiver to handle the longer 3 1/2" shells. The Breech Bolt V4, Fore end Tube V28, Fore end V29, Slide Assembly V57, Trigger Plate Assembly V65A, Since the receiver is the same size and the shell latches are in the same place, it seems to me the 3" parts should work?
Michael