[DonVoigt]

Yes, probably the wood has shrunk.

I've had some success by cutting a thin strip of electrical tape and placing on the frame where the grip rests, maybe two layers. You can experiment , no permanent change is done.

If you want to shoot, change the grips to another set; or for a permanent fix, add epoxy to the back of the wood grips to make them fit- I would not do this unless they are "shooter" grips only.

Tape also works in place of the O ring, just place on the frame at the bottom where the grip rests.