I picked up a LMT high strength(super bolt) & opened it for this conversion. Also turned a 16.5" Shilen brl. Mid length gas setup. Breakin rounds(all 20) went into one hole @ 50yds. I was running the 225g Hor. SSP to 1700fps avg. This bolt should give me 45K psi to work with. I am working on the upper limits of the 338BR. 338Whisper was a no brainer.