I've got this issue here, when the mag is empty the bolt wont always lock back like it used to even after doing the bolt catch mod and making sure the bolt carrier is still square. Now when I manually pll the charging handle the bolt will always lock back on an empty mag. After doing some research here it can be a number of things. I haven't noticed any unusual wear on the nozzle or the bolt carrier and I'm beginning to think that the blowback isn't giving the bolt carrier enough energy to overcome the buffer spring and send it far enough to engage the bolt stop.
Has anyone tried to trim down the buffer spring little by little to the point that it could possibly fix this problem and increase the dependability of this function? I understand that the felt recoil may be reduced but I'm alright with that.
Edited by yellowthunder, 02 August 2013 - 02:13 AM.