Years ago I shot a 7mm Rem Mag and found the best bullet for me was the 160gr Speer HC. Heavier bullet's upped the recoil to much and didn't do a lot more. Lighter bullet's got torn up with the velocity. Had a 760 in 280 at the time but never fooled with it a lot, I much prefer bolt action guns. Can't even remember what bullet's I used in that 280.
If I were to get a 280 today, I'd probably start right out with that 160gr Speer bullet. Then to I doubt I'd AI the thing. I'm not so sure it could catch the 7mm Rem Mag and you'd fine a situation if you were off away from home hunting and ran out of ammo or more likely didn't take enough, you couldn't find factory ammo for it. Something I have ever done only one time is take not enough ammo. Actually took enough but took a 28ga shotgun and 410 ammo. Only ever happened one time!
Anyway I think two of the best cup and core bullet's in 7mm would be the 154gr Hornady in a 7x57, had two and in 280 or bigger 160gr. I believe having a need for a 175gr bullet in 7mm simply means you need a 30 cal rifle!