Why does the magazine extension have to go? I used a Mossberg 500ATP 8 shot shotgun for hunting for a while. I just got a wooden dowel from Home Depot and cut it to a length for use as a plug. I was only allowed 5 in the gun in my state so I made it so the plug let me put 4 in the tube, and I would load one in the chamber. Had a few rangers ask if it was plugged, I'd say yes, and that was the end of the discussion.