Functionality issue:  Over the third round I get a lightweight hammer strike.  I have tried using both equally H2 and H3 buffer weights.  H2 I was only having a single shot, H3 I now get two shots off.  I have attempted this on two uppers, a single carbine and one pistol, but using the exact same BCG.  I ordered an aimsurplus NiB BCG, I am gon