Re: AI stock on a Remington 700
There are only a couple things that could be twaning, its either the magazine under recoil, or the bipod springs (most likely).
But to make sure, I would take the skins off, and make sure that the aluminium tube in the stock is still secure, for and aft of the action. Little chance that it is not, but better safe than sorry.
Most likely its your bipod.