People have been using rockite/ quickcrete type products to stiffen/ add weight to the axis stock since they first came out. On the ones I’ve done I’d didn’t fill the forearm up to the top of the reinforcing grids. Nor did I use near as much in the stock as txtrout shows. The rocketed did stiffen both the forearm and wrist area and did add a little weight. I liked the Rockette stiffened stocks better than Boyd’s stocks. These were older original axis stocks.