Generally when Lot testing or making adjustments I'll clean after every 50 or so pellets through the bore as I'm usually shooting all the same Brand of pellets. Unlike with rimfire, I don't know if it makes much difference if you clean when changing Brands, but it definitely wouldn't be a bad idea. Of course, when I'm shooting in competition I'll clean after every card, which usually ends up being anywhere from 35 to 50 shots.
Dave
