Harry,
I have a new Merkel .300 WSM with a Zeiss scope. It was a gift from a good friend and it cost more than my truck! It shoots like a house afire and I can't wait to reload for it. I shot 3/4 of a box of Federal premium ammo. (about $60 a box - came with the gun - what a friend!) through it so far and I can tell it's going to be a very accurate rifle after I break it in some. It will shoot 1/-1/4" now for 5 shots at 100 yds. I know it will do 3/4" with the "sweet spot" loads. The .300 WSM is hot! Let us know how yours does and your favorite loads.
Thanks,
BT