I would reconsider converting your Rem700 to 338 Lapua.
I think the Remington action is barely able to properly handle the 338 Lapua or 300 Norma type rounds.
If I recall correctly you have to open up the lower feed ramp for proper feeding because the Lapua rounds are bigger in diameter on the cases. This makes the bottom bolt recoil lug of the receiver thinner which can in my opinion compromise safety.
You will also need to open up the bolt face for the Lapua round and change the extractor over to a M16 type extractor.
Also the thread size on the Remington actions leaves the chamber area of the barrel thinner. This has been proven to cause more barrel stretch/expansion which can cause extraction issues of a fired round. That's why you see more aftermarket receivers that are set up for 338 Lapua have a bigger thread tenon and or bigger bolt body diameters or both in order to handle the larger diameter rounds.
Can and has it been done to Rem700's? Yes. Again my opinion it makes the action weaker.
Buy a action that is set up to handle the Lapua rounds specifically. By the time you invest $$$$ to convert/modify the receiver and bolt you will have X amount of $$$ into it. Might as well buy a new action and save any headaches you might encounter.
Here at Bartlein we will not install/modify a Rem. 700 action to handle the Lapua/Norma type rounds.
Later, Frank
Bartlein Barrels