I picked up a chronograph just long ago enough to run my first good series of tests.
What I'm finding is that with the pistol calibers I can get the s.d. down in the 6.0 to 10.0 range with little or no problem. But as the caliber go's up so does the s.d. My .223 is around 9.0 to 15.0, my .308 is up to the very high teens to mid twenties and the 30-06 on the very best days is in the mid forties to high fifties.
Is this normal?
I assume that the instructions that came with the chrono were correct in that the s.d. is no more that a averaged number that gives a idea of over all shot to shot consistency.
I find it tough to believe that I can get good results loading .223 and do fair at .308 only to have 30-06 be so far out in left field.
OBTW I'm shooting .223 from an AR, .308 from a Rem. 700 and 30-06 from a DCM Garand.
Many thanks to all that respond for their thoughts on this matter.