I have Grovtecs in mine, with a heavy 26" barrel, Atlas Bi-pod, and NF scope. No problems at all. Just used a good epoxy and drill the holes a little tight so the cups screw into the stock a little.
Secondary question. I installed Grovtecs in a HS Precision LTR stock without any problems. I am doing it on a second HS Precision stock and when I drilled into the buttstock I am finding a lot of white foam strips inside. What is the purpose of the foam strips?
In the rear or front of the stock? The only thing I can think of is that someone placed a weight in the rear cavity of the stock and used foam to secure it or fill the void? Other than that, I have no idea.
My hole for the Grovtec is in the rear about 1.5" from the recoil pad in the center. I can visibly see inside and don't see any weights, just a hollow buttstock. I pulled it all out, but will probably just shove it back in prior to epoxying the Grovtec base.
I've only replaced the pads on a few HS stock and have never seen anything in there that wasn't put there deliberately. Again, only done a few.
I'd say its probably not hurting anything so its up to you. Good luck!
I figured it was to dampen the sound or to suspend bits and pieces that rattle inside the stock. I ended up pulling a chunk of epoxy and cut piece of plastic from inside that I never would have heard previously. I pulled the foam and will just spray a squirt of "Good Stuff" to dampen the sound.