.348 brass, unless it is drawn, is only 2.1" long. Too, it has a .545" head and needs to be turned smaller for the .280 - something I have difficulty with. Donnely's book explains doing just this, but I still have a problem with that process in a round that developes around 60,000psi.

Standard Magnum brass can easily be altered by blowing the case out foreward of the belt. I've made 8x68's from .375H&H using this method with perfect results. Altering the brass by turning the belts to .522" was a 10 second job.

For the Ross, the belts would be left full diameter & the .003" discrepancy is within normal specs, as long as the rifle's chamber isn't oversize. I would use .375H&H brass, not .300H&H, as the .375 brass is easily obtained and altered.