Hey guys, I have 2 G&P upper receivers as shown in the pics below. One is a VLTOR and the other is a regular one. On the right, is a Classic Army delta ring from my old gun. The delta ring screws fine in the VLTOR upper, but doesnt screw in for the regular upper.. BOTH are from G&P..I also tried the nut from madbull and it still doesnt fit on the regular upper (as expected). I also used a bit of oil but no luck. Any ideas why?
