Here's my 2¢:

I want my bedding compound to be hard, so it does not compress when the action is torqued into the stock. Temperature stability without expansion and contraction is important as well. Just because no one has tried it, does not mean it won't work, but I'd try a sample block first ( you could fill part of an old ice cube tray after coating it with release agent, and when the ice cube of your epoxy was fully cured, you could test it to see how hard it is. If it is designed to be a permanently flexible adhesive, It probably wouldn't be an ideal bedding compound. However, if not, and it works for you, let us know; we're interested!