Just shot a match a few weekends ago that it rained the entire weekend. Got back to the room, took my action out of the stock, wiped everything down with rem-oil wipes then dried it off with a towel. put it back together and Re-lubed/greased everything like I do as normal maintenance and set it aside for day 2 of the match.

Just wipe it off and don't leave it wet. If you're going to store it after it building up condensation run a patch down the barrel followed by a couple dry patches.