Are they hard going back in as-fired? If so, in the strictest sense, and regardless of how the brass looks, that would be a pressure sign in that it means steel is moving outside its normal closed action volume. It might only be due to a loose or bent pin or bolt lugs in need of lapping, rather than pressure being high enough to be dangerous. But, it's still a pressure-dependent variable, so it might help explain at least a portion of the differences in fired case lengths you are getting.
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