When we first got the Thumper we had issues getting the velocity up, so i shimmed the spring with a washer or two. and it was fine.
After it went back to Metadyne he installed the steel hammer and i removed my shims and it easily clears 300fps.
I find it hard to believe that turning the reg all the way up causes miss feeding. the pressure of the gun has nothing to do with the mechanical action of chambering a ball.
auto-triggering is not recommend because the gun is trying to fire while the air chambers is trying to fill, causing o-rings to fail. it seemed that everytime we had a piston failure it was while someone was auto-triggering(on the older small piston)
Re-balls and paint chrono very differently in a Thumper.