Forming 7mm SAUM from 270 WSM Any Experience?

[ReplicaSnipers]

I am looking at a barrel for my Tikka T3 Varmint as new in 7 SAUM 30” 1:8 twist to shoot 195gr Bergers or similar that I cannot stabilise in my 1:9.5 twist 7mm Rem Mag. Problem now is brass availability with it being near unobtainium in Australia and ridiculously priced. However I can get 270 WSM for a good price for Winchester brass and have heard you can reform it to 7 SAUM and trim to length. However I note the rim diameter is 0.001 wider. Will this make any difference? I’ve had good luck forming .308 Norma Magnum from .300 Win Mag Winchester brass without many dents in the shoulder ?brass thin and soft but I’ve heard the 300 WSM brass is a bit harder than other brands? Anyone with experience of any of this? TIA.