I have a classic mag that used to vent out the back whenever I tried to go above 270fps. I gave the allen screw in the reg piston a turn or two and this fixed the problem. But when I turned my velocity up enough to shoot around 290fps, there weren't enough threads on the adjuster to attach my tournament lock. So a few stainless steel washers from the local hardware store between the adjuster and the spring pack, and I can attach the tournamnet lock again.
That's what I used them for.
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