I've had a Chrony for about 12 years and it's been as dependable as the sun rise for me. I've chronoed LOTS of varmint bullets, muzzle loader bullets, pellet guns and arrows and it's VERY consistent. I can chrono my bow with a certain arrow and a month later it will read the same speed and it's VERY close to what BowTech has on their birth certificates they ship with their bows I'll buy another one when this one gives up[8D]