Methinks you guys are fulla beans... again.
Butler in 'The American Shotgun', quotes a series of SAAMI tests. On page 197 of his book he shows a 'three foot coil measurement' of an undescribed load as 1336 fps. He equates that to a muzzle velocity of 'slightly over 1350'. That's 14 fps folks, or a little more, not 100.
The discussions and graphs in the same source refer to 'muzzle exit' conditions of a 3 DEq one ounce load as 1,284 fps, a figure we've accepted as reality for good long time.
The other references in this chapter are to 'muzzle velocity', not three foot velocity. The one instance of a discussion of exterior ballistics refering to a 'three foot' measurement shows the above mentioned +14 fps loss.
My own chronograph experience shows very little difference in recorded velocity with several feet variation in muzzle location relative to the screens.
Factory velocities are very close to advertised over my machine, and my handloads usually chrono scarry close to the published velocities. Again, I can back off a few feet or stick the muzzle almost even with the back of the machine and I don't see very much velocity difference. Certainly nothing approaching 100 fps in the first three feet!
I call BS on this one.
Last edited by Shotgunjones; 02/18/14 11:34 AM.
