Over the course of ours on the trail walk, the buildup of powder fouling in the breech was evident, however it never hurt accuracy. What we would see
as a steady creeping up the rod from the loading mark as the fouling built up and reduced the 'chamber' area. This did not hurt accuracy, nor did it disturb
ignition. Depending on the bore, the same charge and patched ball on it, would show about 1/4" above the rod's mark. This is normal and nothing to be
concerned about. This would be after from 30 to 60 shots - no wiping nor swabbing at any time. We've even done close to 100 shots, NP AND no fouling
buildup in the bore, just at the breech.