Years back I was given a J.C. Higgins M50 rifle in 30-06 from a late friend. he'd made a nice stock for it and I hunted with it for years. One day I took a bad spill and the rifle's stock broke at the wrist. A few years later, quite a few in fact I came across a Buter Creek stock for a Mauser action for $50 at a gun show so it came home with me. A little bit of inletting work and glass bedding and the rile was a shooter again. I didn't like the "booming" every time I bumped into something so figured I'd fill the hole in the butt and barrel channel with something. Just had to figure out what? While at a hardware store, I saw this insulating foam that expanded after you inserted it into whatever cranny you wanted to fill so I gave it a try. First I filled up the butt and quickly got the buttplate back on before it oozed out all over everything. Then, I masked off the edges of the forearm and set the stock in my paded vice. I used two layers of black electical tape on the bottom of the barrel and some grease I had on hand to act as a release agent , shot the hollow barrel channel with the foam and quickly got the barreled action ito the stock. Ater the foam had time to stop expanding and was stiff enough to trim the excess off the forearm, I took care of that. I left it in the vice overnight and when I took it out of the vice the next dat, I used a black Sharpee pen to color where the tannish white color of that foam showed. I bolted the gun back together and with some loads I knew it liked went to the range. The gun shot better than ever and I'm thinking that foam in the forearm really made a difference. What extra weight the foam may have added seems to be neglibile.
A while back I bought a Winchester m70 Stainless Classic and the tupperware stock on that gun is the worst POS I've ever seen. The stock flexs like a snake on a hot griddle. Accuracy is barely good enough to hit the inside of a barn. I'm thinking of trying the same approach with this one but with the addition of a threaded steel rod in the forearm for addition stiffening. Jut have to get of my lazy read end and git-R-done.
Just thought you might want to give something likethat a try.