Gough Thomas, writing 50 years ago in reference to the 25" Churchill barrels, gives a velocity loss of 30 fps, going from 28" to 25" barrels. But that was based on a study done in the 1920's, when Churchill was defending his short barrels against the naysayers. Thus, the shells in question likely were not of the modern, post-Super X variety with progressive burning powder. I'm guessing the difference with current ammo would be even less than that.

Last edited by L. Brown; 08/16/12 07:49 AM.