Shoot your test loads off of a bench rest and go with the best groups. I load 5 rounds of each. Haven't got a chrony yet myself. It is important to see velocity if you are trying to make power factor for ISPC/IDPA
how much does a chrony run you anyway i think it would cool to test velocities out of your gun and once i get better at reloading if love to try to work up some loads but you kinna need some way to emasure velocity for that eh?....