My problem wasn't slightly dinged cases. It was the bolt folding the follow up case on the feed ramp, because it was running way too fast. It just smashed it all to hell. This was with a std M16 carrier, not lightened. I had to bump up my buffer weight to slow it down. This eliminated the problem completely. What was happening was the BCG was moving wicked fast & rebounding off the back end of the buffer tube. This caused it to outrun the mag. The carrier would be 1/2 way thru the cycle by the time the next cartridge was in position. This caused the bolt to contact the cartridge at about halfway up the case instead of on the rim & push it against the feed ramp folding/smashing it. Had I been using a lightened carrier it would've been even worse.
So my statement about compensating the reduced weight carrier with a heavier buffer was, what's the point. You still have the same amount of reciprocating mass. To use a light buffer & light carrier like the JP LMOS, the reduced gas is necessary to keep your BCG from running too fast. I guess it doesn't have to be an adjustable gas block just one that reduces the amount of gas (smaller bore) back to the carrier.
BTW: this was in an 11" SBR which by all accounts is supposed to have less gas at the carrier that a std 16" carbine, since the gas port is so much close to the end of the barrel.
