Many smiths will do it, many won't. It's really your decision. My brothers 338/378 is working fine and I know many others who have the same experience as well. I have talked to ALOT of smiths about this and they know MANY more that have been done than I could imagine too. Not even one had a problem, even so only about half were convinced it leaves enough margin of safety. I will have mine done without worry, but I suggest you do the research as I have and you'll find the same. Wheather you make the same decision is up to you, but I'm confident you WILL find the same thing I did.
I talked to Dave Tooley yesterday about it concerning a 300/338 Lapua Imp I'm working on getting done up and he's in the "don't wan't the liability" camp as well.
I know one smiths favorite LR mountain rifle to build and shoot was the 700 in 30/378wby. The smith I use has about 25 center feed mag boxes of his for the 700 that he designed and made for the wby cartridge.
I have gotten countless emails from guys wanting load data from my brothers to use in their setups and to let me know how theirs is working out over the last two years.
They use Sako extractors and alot of them are just single shots for LR use.
Good luck.
