Re: I need a little help here
Single shot only.
Pre-fit Savage barrel. You can find it when you type "pre-fit savage barrel", depending the coutour. Midway, Brownells, etc...
Change the bolt face from .535 to .588 from Midway or Pacific (may need new needle? not sure)
If you plan to use 338 Lapua with 300gr Berger OTM, you may have to push the bullet down if the gunsmith use the standard 338 Lapua reamer. Tell him to drill the throat a bit longer for 300 gr bullet.
Otherwise, use 338 Norma Mag which is a bit shorter than Lapua and you can push the bullet further.
Just a thought.