PJ the only info I have on the 480 is out of a 7.5" barrel. The load manual is showing 1258 fps with 20.5 grains of H110. That is max. load .The starting load is 18.0 grains . The bullet is a 400 grain HDY XTP. This info is out of Hodgdon manual. I hope this might help some .By the way col is 1.620 with the Hornady bullet.