I think the SAUM's shoulder is closer to where you need it, probably just neck it down and fireform like can1010 stated (I'm not real familiar with the SAUM).
The biggest problem I see is availability of the SAUM brass, definitely less available.
If the brass is new, I don't think annealing would help any.
The 7wsm may actually be a little easier than 270wsm when it comes to pushing the shoulder back since your starting the push back in the neck area.
With the WSM cases you may have to ream the portion of the case that gets pushed back, good chance it will be thicker in that area
Years ago when Rick Jameson was still at shooting times and he had his line of cartridges, I had a .338 Jameson built and formed all the cases from .404 jeffrey brass (still have the dies), which came with a reamer. Later I converted that rifle to 270wsm and initially turned the 338 jamison fromed brass into 270wsm, if I remember right I ran them into a 300wsm die than the 270 die. I now have Norma 270wsm brass.
My point is that I think any of those cases will work!
The biggest problem I see is availability of the SAUM brass, definitely less available.
If the brass is new, I don't think annealing would help any.
The 7wsm may actually be a little easier than 270wsm when it comes to pushing the shoulder back since your starting the push back in the neck area.
With the WSM cases you may have to ream the portion of the case that gets pushed back, good chance it will be thicker in that area
Years ago when Rick Jameson was still at shooting times and he had his line of cartridges, I had a .338 Jameson built and formed all the cases from .404 jeffrey brass (still have the dies), which came with a reamer. Later I converted that rifle to 270wsm and initially turned the 338 jamison fromed brass into 270wsm, if I remember right I ran them into a 300wsm die than the 270 die. I now have Norma 270wsm brass.
My point is that I think any of those cases will work!