When you set the chrono up 10' to 15' from the muzzle, how much velocity is lost in that distance? Or is this considered muzzle velocity? Want to know for ballistics program. Thanks, Steve

I always just use it as muzzle velocity. You are likely only loosing (3-5)fps or so. It really has little bearing on the numbers. AJ

Thank you, That is what I thought, but someplace in the back of my head, I thought that I had heard a more significant #. I will quit worrying about it. Thanks, Steve

Steve There is a simple way to find out if your chronograph has a proof channel. Set your front screen 10 feet from the muzzle. Fire a round. look at the difference between the proof screen and the record screen. If you have two feet between each screen and the velocity difference is "Say 5 ft/sec then you would have a true muzzel velocity of 30ft/sec faster than the recorded muzzel velocity. (25 ft/sec for 10 ft + 5ft/sec of proof screen= 30 ft/sec). One foot would be (5x10=50 + 5 = 55 ft/sec Simple J E CUSTOM

go here http://www.eskimo.com/~jbm/calculations/traj/traj.html put your data in and set the distance from muzzle to chronagraph and it'll tell ya your actual muzzle velocity. My 6.5 gibbs gains 8.2fps w/140 from 15ft to muzzle. RR