I'm having a 300WSM built on my old Win Model- 70 30-06.
It. Requires opening up the bolt face, & playing with the rails, but to have a long action WSM is freakin Awesome!
J.E. did a post that's now a "sticky" in the gun smith section on bolt face diameters, & smart options. It's definitely worth a look!
Sky is the limmit on standard length long action rounds, or short action rounds on that action tho.
RUM, & STW Length may not be possible, but I don't know that for certain.
There are quite a few excellent smiths here on LRH. My advise would be to call a few, or p.m. a few of them for specific answers.
"shortgrass" (Ted at Teds custom shop)
"coyboy" Jim See (Centershot rifles)
"fiftydriver" Kirby Allen
"Shawn Carlok" (Defensive Edge)
& the latest LRH sponsor/gunsmith making a really great name for himself "grit".
Any or all of these guys, and more come to mind. LRH has some Excellent sponsors. Id feel confident using any of them.
"Its not Rocket Surgery.....'
GOD,GUNS,&GUTTS MADE AMERICA, LETS KEEP ALL 3!winmag
"I have No idea why that cop made me ride in the back seat, when I Clearly called Shotgun!"