Re: Remington SR-8 .338Lapua
GA Precision builds them all the time, Chris or George would be the ones to talk to. George knows quite a bit about the SR8 as well.
I've got a 30-338 Lapua Imp, my Brother has a 338/378 WBY, both on the Remington 700.
S1 at ARTactical.com build a 30-338 Lapua Imp as well, calls it the 30 WOLF.
Good luck with the project.