I know where there is a new old stock 700 bdl ss in 300 rsaum I can buy it for like 400 any issues as far as action length for a 257 wsm I heard some remingtons were a little shorter.
The Remington short action is one of the shortest around - thus the shorter COL for the SAUM v. WSM. I'd consider something else for that action, or leaving it alone, as a nice stainless 300SAUM is a great hunting rifle. Load it with a stoutly constructed 165gr and you'll be very pleased, I bet. At $400, it's a steal. Wish I had the coin.
Maybe I'm missin' somthing here but could you just neck down and rebarrel your average 270 WSM?? Then youd have "factory unfired" brass and an action etc. CL