With my high round count GP100s, I make sure to take a 40 cal boresnake (if I'm running a 357) in my range bag. Usually mid-match, or at the end of day 1 if it's a two day match, I'll take the boresnake to the charge holes. If I'm running my 10mm GP, I use a 45 ACP boresnake for the same effect. This is in addition to brushing out under the extractor.