Operate situation:  About the 3rd round I get a lightweight hammer strike.  I've experimented with equally H2 and H3 buffer weights.  H2 I was only obtaining one shot, H3 I now get two pictures off.  I have tried out this on two uppers, a single carbine and a person pistol, but using the identical BCG.  I purchased an aimsurplus NiB BCG, I'm p