So I've had my 450 Bushmaster since September 2011. I bought a complete 16" rifle package from Gander Mountain. Since the day I got it, my front take down pin hole in the upper itself has been very tight. So tight that I have to use a wooden dowel and a hammer to move the pin. I took the upper off and put it on my Rock River lower, same issue, put my Rock River Upper on my Bushmaster lower, no problem.
So I believe the problem would be the front hole of the 450 Upper where the take down pin goes. What can I do to loosen this so I can switch out uppers without having to carry tools?
Thanks guys!
B.