I shoot South African .308 milsurp in my Ruger M77Mk2 International. It works splendidly! I love it! It is pretty darn accurate. Just screwing around with a towel-over-jeep-hood-rest, it placed 3 rounds you could lay a penny over and cover at 80 yards.
The South African is pure all-copper jacket, by the way, if anyone was wondering. I tested it with a rare earth magnet that detects even small amounts of steel and it didn't so much as wiggle. In the 140 round sealed battlepack, it's a helluva deal. And it shoots just as good the name-brand FMJs. The only caveat with milsurp is to be sure you clean as if the ammo is corrosive because it probably is. Nothing to be afraid of, just use the proper cleaners. The bore of my Ruger is still shiny, sharp, and like new and I've fired lots of South African through it. Milsurp is one of the benefits of owning a .308 bolt.