Have a used Colt 7.62 upper with a non-stock gas block. It has a allen screw that adjusts gas output. Why would this be desired? Have to back the screw out 3 turns to cycle bolt.
Posted: 4/22/2009 8:08:59 PM EDT
[#1]
Suppressors usually need a way to regulate gas to the bolt, and possibly different ammo.
