I remove the barrel for water busket flushing with cold water when cleaning at home - dry with 4 or 5 patches, then spray liberally with WD40, then patch out and wipe down, reassemble and store muzzle down. At rondy, I plug the vent & fill with cold water (mostly) let sit for 15 min. drain, re-plug and fill a second time, then patch out with dry patches until dry and clean - 5 to 8 patches, generally. Our matches at rondy are all around 20 to 22 shots - very little buildup in the breech, none in the bore except for the last shot. One can also drop in a 20gr. charge, seat a very heavily wetted cloth patched ball on the powder, then fire that on a plate - poooot! The bore will have way less than 1/2 the normal breech fouling as it was cleaned by pusing down the squib load, and the fouling shot out with the ball. This makes it even easier and faster to clean due to reduced breech AND barrel fouling. After wiping clean and dry, it is then given the DW40 treetment. Locks are always removed for brushing with water, then flushed with WD40, excess of which is then wiped and shaken/blown off. No rust at any time - before or after.