RE: Does a clean barrel affect patterns?
On a shot to shot basis I don't personally think it makes that much difference. On a long enough time line plastic fouling will build up (espcially around ports) and that will reduce the effectiveness of them. When I clean the gun, I use a brass brush and a DeWalt drill.... and there ain't no plastic in my bore!
The patterns I have all come from dirty bores.... and from the way they shoot, a clean bore ain't worth the effort because they can't get but so much better.