I talked with one of the Chandlers from Brigade Armory at the recent Richmond VA gun show. We got discussing the 700 in 338 Lapua coming out. He told me that he did the testing for Remington on the 338 and the CM action tested very good and higher than the SS actions. More than enough to handle the 338 Lapua.
We discussed Dan Liljas testing and article that has been around for years on the 700 action and large cases. He agreed with part of it and if I remember right, he was talking about a difference in the 338 extractor vs the standard 700 and a couple other tweaks. He who gets one in his hands can update that info.
I have based my statements off Dan Liljas testing of the 700 action which has been the most highly acknowledged info available on large cases in the 700.
Lilja Precision Rifle Barrels - Articles: 378 Weatherby Cases in the Remington 700 Action?
You will see that the 338 Lapua is only .003 smaller than the Rigby case.
Guess time will tell if this is good to go.
For the money and extractor issue, it now makes sense to just buy a new bolt from Dave Kiff with the extractor placed correctly and it will be cheaper than reworking an existing bolt, plus you can sell the old bolt for 75% of what you paid for the Kiff bolt.