Can't you just set it up close at the end of the muzzle?

 

The difference is fairly small, given the average velocity of whatever ammo you're shooting. I have several external ballistic programs for doping out my chronograph readings. Normally, I set up at approx 13 to 15 feet from the muzzle. When factoring in the programs settings, it usually compensates a few fps additional for true muzzle velocities. For anything over 2500 fps, just figure 3 to 5 fps difference between muzzle and chronograph.

 

Piggy....you set it 12-15 feet away to avoid damage from muzzle blast.

Misiu....the difference is so minor it's not worth worrying about, and since most people chronograph to compare different loads or brands, as long as you have it the same distance from the muzzle in all tests, you'll get valid comparisons.

 

"Standard" distance to chronograph screens for MV is 10 feet. That said, if you are shooting black powder or hot loads in a short bbl (flamin' dragons) you want to set farther out to keep the flame front from giving false readings. When we chrono my friend's 22-250 with the short bbl, we have to put it out to almost 18 feet.