Burn marks

[BMiracleTX]

Completely normal with lower pressure loads.

[ReneeMicelli]

That's pretty typical with lighter loads. All my light pistols loads do that.

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I agree 100%. Lighter loads do not build enough pressure to 'seal' the chamber fast enough to prevent blowback from coloring the case. All of my competition loads do this. I run them at the lower limits of making power factor and this is one of the side effects. It is not a bad thing as long as you are not getting squibs. Just something to deal with.