This was a standard practice on many custom rifles. More to get ideal balance than any great weight reduction. Even with a full Swiss cheese treatment on dense wood I think about six ounces would be max. Look at the Boyds light weight option, keep in mind you can remove more material with a laminated stock due to the inherent strength.

I have also saturated the holes with epoxy to seal them and add a minor amount of strength. The British smiths would plug the holes for cosmetic reasons and to make attaching butt plate and grip cap easier.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli