I recently changed the gas block on my DPMS upper with a low profile DPMS one. Now it short strokes. The bolt barely clears the back of the mag when it cycles. It will cycle anywhere from 8 to 10 rounds before it won't cycle far enough to strip a round. When I run the mag dry the bolt actually locks back on the mag follower, not the bolt hold open.
Now, some history on this upper. It has done this same thing with the old gas block, however it was shooter dependent. I.E. it happened to everyone else, not me. Also, I took it to a gunsmith a while back because if you chambered a round you COULD NOT extract that round. The case was so tight in the chamber you had to fire the weapon to unload it.
Is there something I should be looking at, or should I send this thing to a gun smith? How can I tell if the GB is lined up properly I don't know of any true GS's here in Fresno area. There are some who advertise as GS's, but they're the guys you take your gun to to have drilled for a scope or something simple.