shutter stock barrell (sucks ass as everyone knows already)
Red shutter w/20 oz.
32 degrees precicion barrell (just as good a s a boomy)
el tigre and allstar (2 smallest bore balls on the market, the precison has a small bore fit and these balls work best)
everything really . broke one ball, and it was a running shot so it prolly messed up the shot. you know how you hold the gun afects your chance of breakage . but its really quiet and accurate. shoots real far too.150 fps no prob.
nuthing. except that you need to make to make sure you got small bore balls.
this is barrell is just as good as the highly overrated dye boomstick. its like 30 $ cheaper too. my friend had one and my barrell is shooting better than his boomy. it could be his gun though. he has a piranha g3 pro and i got a shutter.