Excuse blurry pic,only one like this I have(taken yrs. ago,1st. I used camera.
I designed this exspanding stem to exert as little pressure downward as possible with the major pressure being exerted outward,I found a single expander button tends to crush cases somewhat
The diff. in rim diam. has not caused any problems in the rifles we shoot,if you meaured several factory cases you would find they are far from being uniform.
There are 3 or 4 more notes concerning case annealig and so on,but I think this is enough to get the general idea,I've made cases for all the WSL rifles,use 32/20 for the .32 WSL,38spl for the .35 WSL,357Max. for the .351 WSL,had to go to 357Mag when 357 Max. got fairly rare/costly.
RayP.