.223 perhaps? Seems to be a pretty common complaint, a lot of AR guys won't use Federal.
, but I do use 223 Lake City which has had no problems.
Often loaded pretty hot, even in factory ammunition.
This too. Loading to a full 65,000 psi seems questionable as at that pressure slight variations can jack pressure up to too high. Case capacity, powder lot, fouled bore, high temperatures can put a hot load over the line.
