Not sure if it's worth adding anything to this thread seeing where the page that opened has gone. However, I tape - with plain old cheap black tape, whatever's on hand. I've picked and blown snow out of too many barrels not to. I've also melted out solid plugs of ice on occasion. That ain't no treat considering what a heat sink a standard contour barrel can be. As for rain getting in, had that happen on taped barrels too. It's something to consider and be aware of if the barrel matters to you. I don't carry muzzle-down when there's liquid moisture flying around. Then again, I'm not one to carry with a plugged breach either, so fired, neck-sized, fl-sized, etc don't matter. Barrel obstructions do. Ringed barrels aren't much fun. Tape doesn't solve everything, but it eliminates a lot of trouble. Now I need to figure out a better way of cleaning the snow away from the port before the bolt is opened and allows a shower of chamber wedging crumbs from entering. (And that's one of the reasons I don't size my cases to near snug fit.)
Sometimes, the air you 'let in'matters less than the air you 'let out'.
