Just a thought here, I am an avid groundhog hunter in western Pennsylvania. As the summer days have gotten very humid I have noticed the fouling in my barrel go from 30-35 shots per cleaning to 20 shots per cleaning and when I do clean, the barrel has more carbon fouling than it's ever had for that many shots. Is there any merit to the humidity in the air causing a "caking" effect on carbon fouling? My pard also noticed this in his rifle. For details sake we are both shooting 22-250s with h380 powder. My cooper has a Wilson barrel on it and his has a hart barrel.