The difference I see is the 7mm will hold more powder, and is capable of handling bigger bullets. Say, 160 to 175 gainers better than the 280. Rem. The 280 is more efficient on powder and you can achieve the same velocity with less powder, as opposed to a 7mm. I shoot a .280 hand loaded with 140 grain bullets. I like the 280. Always been an odd ball though.
Sorry, but a 280 will not get the same velocity with less powder.
