Interesting ... I was doing a little research on bark inclusions in gunstocks. I found these two pictures of inclusions on a maple gunstocks, including the way the makers filled the voids. Looks remarkably similar to what's going on with my Garand stock, including the long worm-like nature.

Screen Shot 2023-04-27 at 4.57.44 PM.jpg

Screen Shot 2023-04-27 at 4.58.36 PM.jpg