I already have an R1, looking at getting a new barrel, ideally this will be capable of going to Alaska with me some day, and many outfitters advertise that they require a minimum .300 win mag (need to actually talk to a few to see how they feel about 7mmstw). This brings it down to .300 vs .338, I don't actually care for either cartridge. That being said, I have never found an instance, hunting, that couldn't be solved by the .300 that the .338 would have solved betterer, especially with bonded/partition/monometal bullets.... soooo is there any REAL reason to go .338? This will only be shot enough to stay proficient, not a regular use rifle.