When I started loading cast, I had both a Savage 99 in .308, and a Marlin 336 in .30-30, both used the same bullets... a 173grn FP. I loaded up test loads in both cartridges with the same loading data... everything the same except, of course, the cartridge case. 28grn IMR3031 in the .30-30 case gave me 2000fps out of the Marlin, but only 1775fps out of the .308 Savage.