I got a Stag left hannded Upper about 6 months ago. The past few times I took it out I would get about 20 round out of it and the ejection port hinge pin would work its way forward through one of the holes on the barrel nut and he spring spins around and losses it's tention. I called Stag and they told me I had to get a silicon wedge to put between the pin and barrelnut to keep it in place. Not sure if this is happening just because I have a freefloat quad rail. If anyone knows were I could find one of these wedges or if you are having the same problems please let me know. Thanks