if you compare velocities with equal bullet weights, the 280 is like the 7mag plus 50-100 yds
so, shooting a 280 at something at 300 yds is like shooting the 7mag at something 350-400yds out for energy; point blank range is about 50 yds less for the 280
in other words, for most hunting in N America, there's no meaningful difference, with a decent bullet they'll kill pretty much the same at most people's reasonable game shot ranges
as noted, if you're going to push it into long ranges, and want heavy bullets, the 7mag wins, but most 7mags are tougher to haul around all day
