I’m 3 for 3 with gel filled stocks.
Hopefully MCMXI will chime in and can give more info on the history of the Hunter stocks and which ones are filled or not.
It’s easy enough to tell just by holding them and feeling the weight being quite far back or by knocking on them. They’ll sound pretty solid and then the last 2” in front of the recoil pad will sound hollow.
As far as spray foam goes, I noticed they are a little quieter and quite a bit stiffer after filling them but to each their own. I’m averaging about 1.3oz of weight in spray foaming after removing an average of just over 8oz of removed gel.
