I am thinking about filling the stock of my Wolf with expandable foam. I read on here once of someone doing this. Question is, I need to put something in there like PVC pipe so the foam does not cover the bolt that holds the stock on.I thought I saw that someone did this, but I forgot what they used.

Hmm...I've heard of JB weld being used for stock reinforcement. Bet that took some time and money But I'd definitely make sure you still had access to the bolt.