You might consider shipping your 7-08 barrel to a smith and having them punch it out to 284...or doing a little due dilligence on the chambers a given prefit comes with. Some 284 prefits have long throats that won't work too well at short action OALs. A Savage SA centerfeed mag is 3.00" long, so you can get a reamer that puts a 162 A-Max or 175 SMK at ~2.95" OAL and still work in your mag.

http://www.snipershide.com/forum/ubb...Number=3147046

This guy is pushing 175s @ 2.95" OAL to 2800fps in his SA 284...