Marauder 22, regulated, LW barrel - inconsistent FPS

Either a reg issue, or like Odoyle said, breach o-ring . If the pellet isn't sealing or being pushed far enough forward, results will be completely unpredictable. If a regulator issue, call Crosman and see what they say. Take some careful notes, and if you have a chronograph, document 50 rounds velocity. If you have Crosman Premier Domes 14.3, try those. Supposedly the barrel is designed around that pellet. Don't use the hollow points. I've not found the hollow points shoot all that well from my Marauder.

This one is iffy if you are still under warranty. If you are worried about pellet clipping, remove the end cap, and baffles. Should be able to shoot without hurting the shroud. If it makes a difference, might just need new baffles. The pellet doesn't have to touch the baffle, sometimes the air turbulence is enough to destabilize the pellet. Do check before doing this so you don't void the warranty.

good luck