well I filled the forearm with foam--got lucky with my two holes as they were dead on exactly where I needed them--

but a note of caution--I didn't protect the fiberglass stock from the foam on the butt and it mugged up the finish --what happened was I filled the holes with foam and let it expand out and then removed the excess when it got pretty much cured in a hour--I should've used some tape(which I did on the forearm)--I was there wiping off the foam as it expanded out of the hole, but that got old so I decided after it slowed down I'd let it do its thing--shouldn't have--to me this is no biggie as the stock is not pristine, but now I know for future projects---chris