Ron,
I would definately clean it before you shoot it especially if it hadn't been cleaned for awhile. I myself like using a brush after about 300 rounds. But others just patch their barrels. It's sort of a personal preference. I think you should be good to test the different ammos without having to clean it again. But remember each ammo will take some rounds through the barrel to lube it accordingly for each brand to shoot its best. Good ammo ought to start shooting good almost right away or at least that's been the case I've wittnessed with a precison barrel. Your 541 should shoot Eley balck box and red box well. The Wolf Target also will shoot real well in your barrel I would say. My 541THB shot all these ammos well. If you can find some old Fed Gold Medal 900, your 541 should love it. It shot super in mine.
Good luck.
