270 Vs 6.5. In the target world, the 6.5 would be a clear winner on use alone. Then add in the reasons for this.

In the hunting world it would be the 270 on physics alone. The 270 will penetrate as much as needed and puts a bigger hole, not by much, but a bigger hole in the animal.

The above is all things being as equal as they can.

Same can be said about 280 (7mm) Vs 270 in the hunting world.