[dannyboy768]

If I use size 10 o-rings for my bolt tail, there is quiet some friction when I push and pull the bolt with my finger, but if I use size 9 orings, the bolt glides very smoothly but I get a small leak from the hex hole in the back cap.

How easy should it be to move the bolt back and fourth? With size 9, I can point the gun down and shake it and the bolt will move slightly but with size 10 it doesnt glide smoothly at all and I need maybe about 10 oz of force to move it. Sorry I dont have a pressure tester, I know that would make things easier.

[Pdubs]

I use Size 10s, but I lube them pretty darn well. put in the size 9s and shoot it a bit to see if they'll settle, and if not look at a size 10 in a different material.

Oring Monkey sells Viton O-rings in size 10, and they're a tighter fit. Also, square (or quad) orings in 10 might help a bit too.

[BonesJackson]

O-rings don't have incredibly amazing tolerances when they're made. I would keep trying a few *different* size 9 o-rings and see if any of them don't leak.

[harjukewm]

I sometimes run a 10 up front and a 9 in back