The fastest I've seen out of a 24'' .270 is around 3090fps with 140 grains.my favorite 7 mag handload using a Barnes 140 TTSX and RL22, over the chronograph I get 3,250 fps.
But we have to take into account that a 140 grain .277 bullet has a higher sectional density.
.284 140 grains - .248
.277 140 grain - .261
To keep it apples to apples, we want to shoot either a
.277 130 grains - .242 (@ 3200 fps, it's brushing the 7mm mag velocity) and compare it to 140 grain .284 cal
.284 150 grains - .266 and compared it to a 140 grain .277 cal
7 rem mag 150 grains - roughly shoots 3100fps
.277 win 140 grains -roughly shoots 3100fps
7mm rem 140 grains - roughly 3250 fps
.270 win 130 grains -roughly 3200fps
I would say that...
It can be handloaded to near 7mm Mag ballistics