I just received my new chrony and I am enjoying it immensely. Does anyone out there know the formula for converting the velocity given from the point of firing (usually 5 to 10 feet grom the screens)to actual muzzle velocity? I read it somewhere but cannot remember the source.

in the grand scheme of things this 10 feet doesn't matter one bit

With chronograph precisely 10.0 feet from the muzzle multiply recorded velocity by factor .99845

I don't have the formulia handy, but the answer is "not much difference".

Take the velocity change between muzzle and 100yd (book balistic tables are close enough for this step), and devide by 300 (feet). Multiply that # by the distance in feet from the muzzle to the centerpoint of the screens. Add that # to the chrono reading.

Example: MV=2800 - 100yd Vel 2591 = 209/300 = .697fps loss per foot.

Actual chrono reading at 10' = 2850 + (.697 * 10) = 2856.97fps true MV.