In the process of building a sub 8 pound (without optic) long range hunting rifle and unfortunately there are not a lot of options for the my chosen action when it comes to lightweight stocks.

Decided to take the current wood laminate stock to chopping....milling block.

Plans are to hollow out the buttstock and pistol grip area and deepen the barrel channel and add some vents/ lightening cuts in the forearm.

Prefer not to leave the stock and pistol grip hollow and want to fill the barrel channel as well.

Need a good lightweight filler and appropriate resin.

TIA

How much does the stock weigh and how much do you think you're going to cut out with this path? It might make a TON more sense (yes I realize the cost) to go with something like a fibreglass stock. I have a few on match rifles and they weigh very little while being stupid durable and environmentally stable.

I would really advise a back-up plan. When you put light weight filler and epoxy into service to fill chasms you get uneven density. That might possibly have an effect on the grouping consistency of the rifle thanks to harmonics going all wonky. If it ends up bad, you'll want a back-up plan. I've had this experience myself. It might be easier and better to go to a shorter and/or lighter contour barrel and you might consider a titanium action or even a carbon wrapped barrel. Any of those will trim serious ounces from your rifle. The carbon barrel is an expensive but amazing way to cut a huge amount of weight. Fluting/contour/length on barrels works pretty well. Fluting and a fibreglass stock was how my Coach got one of his match rifles to get in at 8.5lbs with a heavy barrel on it. I did the same but with lopping off 2 inches of barrel instead of fluting.

The stock a BVSS which is rather meaty and has lots of places to remove wood.  I could easily remove a quarter of the of it's original weight, if not more.

As for the filler, I was thinking more of a foam that I can cut to size and then epoxy in place.  This would remove any uneven-ness.

Barrel is aluminum sleeved and weight slightly more than a typical magnum sporter contoured barrel yet has a varmint contour and 28" long.  Barrel is going nowhere, except up the mountain.

Old school Savage Long Action with flat rear and SSS trigger.

All ready a great load for this rifle and action is bedded.

Was hoping to find a B&C LA Duramaxx, but they are no longer made.

great stuff spray foam

Funny thing is I have can of the big opening version sitting on the workbench.

Be OK for filling the buttstock and pistol grip area, but I am not sure how it will do with the barrel channel.

Yeah, that's pretty meaty. Might try expanding foam for the buttstock and pistol grip. It's worked ok. For the fore-end... I've had good luck with zero things so no ideas there.