I've had a Shooting Chrony for about 12 years and it's been "almost" bullet proof. I've shot everything through it from .17 Remington to 338 Winchester mag and from black powder guns to sling shots with great results. I've even nicked the guide rods with some big black powder slugs and it still keeps registering speeds accurately. I can take a known bow/arrow combination and it's speed and go out 2 months later and get the same speed. Get the Chrony!!!!