Best rounds i have found are thunderbolt and federal automatch. The manual says use 40 grain high velocity rounds. Usually hp bullets and ones where the bullet spins around in case cause problems. I find the round nose bullets work the best. You can sometimes get away with lower grain bullets but for maximum reliablity 40 grain round nose seems to be the ticket
Plus a scrubbing of chamber then spin the chamber with 0000 steel wool wrapped around bore brush helps with smoothing chamber and keep carbon ring at bay.