You can inexpensivlyconvert out any WSSM to a more potent caliber by necking it up to an ecsisting WSM caliber. I took a 223 WSSM that shoot like crap and converted it to a 325 Corbin. I bought a shilen match grade 8mm barrel at midway for $140.00 a set of 325 WSM dies for $35, $8.00 7mm expander for the resizing die, rented a 325 WSM reamer for $25. Reamed the barrel out just far enough to fit the necked up 223 WSSM brass. cut the WSM dies down to same length as WSSM and I was done.
you may have to turn the outside of the necks if your left with to much brass. (i actually used a 8mm-300 reamer..... its a 325 WSM reamer with a tight neck). I shoot 170 gr hornady round noses at 2500 ft/sec and get 3/4" groups using IMR 4350.
you can do this convertion with any WSM caliber.
i did it in just over $200.00 bucks.