Quote Originally Posted by us920669
Be careful not to shoot the thing, and be aware that muzzle blast can knock it slightly crooked, giving errors when you miss one array.
+1 on this. Try to set your chrono up the same way every time. I set mine at 10ft measured with a tape and put a level on the chrono each time. Bigger calibers will have more muzzle blast and might need to be 12 or 15 ft away to keep the blast from affecting accuracy readings. 3 shot strings can give a fair representation of velocity, but are pretty much useless for es and sd. Long strings make for more accurate data.