As a big fan of the .280, having owned two and still have one. I'd have to point out that the factory ballistics of what is available in the .280 are not nearly as good as what you can handload that round. While I rarely use factory ammo, that is a consideration if you need ammunition and don't have time to load for it.
I own and like the M70 winchester. That would be my first choice in rifles. I've had alot less trouble with them than I have with the Remingtons I've owned which include a .280 in the Remington Mtn. Rifle. The .308 rd has a very wide selection of really good ammo as well as cheap surplus stuff for practice.
My second choice would be the Remington Mtn. Rifle.
I'd love to own a Ruger #1 in 7X57. However, they are a single shot, which would require some consideration. Sometimes you really do need a second shot in a hurry for any of a number of reasons. The 7X57's factory ammo selection is the worst of the lot.
The Browning X bolt is an unproven/unknown quality as it is very new. The A-Bolt, that it replaces, has a poor rep for working under harsh conditions. Personally, I'd stay away from them until they have established a solid rep. E
