Christopher, why would you need a brake with a 257 WBY it only has 22.5 lbs of recoil.
With regards to custom rifles
, I paid about $3100 for mine including gunsmithing and everything else except scope but it did include talley bases and rings.
It's a 338 lapua, Prairie Gun Works m-18 action, Mcmillian remington hunter stock, 28" lilja #7 fluted barrel, and Jewell trigger. $3000 is about right. PGW makes great actions (rem700 style) I think their m-15 would be perfect for the 257. I don't think you would need the m-18. Also I got mine in stainless, but they also make their actions in titanium for lighter weight.
Three things if you do get a PGW action. Tell them you don't want a trigger and get a jewell. Have them make you a scope base or you need to buy 2 front bases. Lastly, You WILL WAIT to get the action...but its worth it!