I use Sako type extractors on all of my custom actions, clear up to the 50 BMG's. I have run some very hot loads through my 338-408, excess of 80,000# (for testing) and no extractor has ever failed to extract or come loose. If its not fitted properly maybe then one could come out. Rem factory 7mm mag rifles were notorius for failing. Smaller calibers didnt have much problems at all. The M-16 extractor is very good too, i have used them on 700's in the past. In my opinon, anything is better than the Rem spring steel setup. IE cleaning rod!
Dave