What were your chamber end clearances?Dshooter said:I asked the OPs question before also, & had gotten this same response about to light of a charge. I wish it were the case but I'm not thinking so. I had the same residue on all my cases throughout an entire charge range with faster and slower powders. All the way up to charges that produced stiff bolt lift and heavy extractor and ejector marks on cases. I know this is of little help OP; but having gone through the same issues, I know what is NOT the cause. I'll be watching this thread though to learn more myself hopefully.
Excess trimming from chamber end lets gas scoot in around necks, preventing faster sealing otherwise.