Shims

[Backyard Bandit]

Ok, I have a LX bolt in my mag and it came with a bunch of little copper things that I assume are shims. Basicly my question is what are shims, and what do they do? My LX is tuned correctly and has not chopped yet, so I assume I should not screw around with it, but I would like to know.

[Dayspring]

The brass pieces are the oring carriers. They change the inner-diameter of the oring. This will stop a carrier leak once the oring wears in. (It goes in the powertube.)

The small thin rings are the shims. These alter the vent point of the bolt & the oring in the carrier. Use the carrier to tune the Level 10. Use the Shims to FINE TUNE.