Just in case this info is helpful:
BW NT10 (All internals minus manifold stock)
Prototype blue insert w/ mod'ed black soft tip
No spacers or body
PSP 12.5 shooting Ultra Evil (amethyst)
iFit .676 insert w/ .684 CF Boomey
Pressure 125-130 @ 290-300
I only had a 010 oring that fit easily. Thicker than Wesr's so the bolt sticks just a hair bit more forward. Enough to see some of the blue bolt o-ring. Shot about 1.5 case that day w/ no breaks. Here are some pics for reference.