Tis has been discussed before with other bows. Instead of th nylon setscrew in the side of the barrel nut you can get steel ones with a brass tip. This is what I use. Another thing you might try is giving the limb bolt that extra 1/8 turn and then let it back itslf out that little bit as you shoot. This might work if it only backs out that little bit and settles. 1/8 turn isn't very much when figuring draw weight and tune.
So far I've only had one bow do this and that was a 2006 P3. Not being a parallel limbed bow there was more vibration.
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