223 will shoot to 300 Yards fine in a bolt action length barrel (original was 20 inches, so that, 22 or 24 would do fine


243 is a nice round, particularly if hunting. But if you shoot it a lot then the barrel goes faster than some others. (for a Savage guy though its just a good reason to get a new barrel!)


6.5 Creed and Lapua are both designed to shoot well out to 1000 yards and be as easy on barrels as you can make em. They are also very inherently accurate.