Some years ago when I was shooting a lot, I don't recall any of the .338 calibers doing squat at those 1000 yard shoots. However, the .300 Win mag certainly did make a name for it's self no question about that fact.
The bloke who does best in Australia uses a variation of the 300 Winchester. It has a name but I can't remember. I think change in should angle and maybe neck lenghth.
Anyway, he has said a few times that one of the major things is powder suitability of available powders for the case capacity.
