It's not the reg you have to worry about it's noid. To high of an input pressure will blow the noid. Bottom out the reg if you haven't aired it up and slowly increase the input pressure via the reg until the gun will cycle. Then to it over to a chrono and slowly increase it to 280-300FPS or lower if your field requires it. You can ballpark it by watching how far the paint is going but if you're not to experienced judging the range and force of a shot then don't do it. You could end up shooting hot or damage your gun, it's best to use a chrono that's what they are there for.