I got an upper from a guy on MeWe. It has an Aero upper and an 18" Stainless HBar in .223 Wylde.  He said be only put 40 rounds through it and it ran flawlessly for him!  The upper did not come with BCG so I got a new stainless BCG from PSA. I have since made 5 trips to the range and can't get it to stop short stroking. I have the upper on a carbine lower. I have tried the following, Tried another lower, another BCG, got a brand new gas block and new rifle length gas tube.  Also t