Yeah mos def the RELOAD SPEED. Beyond that I think they are worried about making it unbalanced in PvP. If they pop the 300 damage cap along with the reload speed then that would buff PvE and not PvP. Oh and no, not more rounds per chamber. You'll have less rounds overall doing more damage because of the final round in the chamber having increased damage. I'm actually hoping for something interesting nobody has though of or seen. It is an exotic after all.