Fixit, the stock is likely quarter sawn which will cause the growth rings to form this way. I improper storage, vertical butt down, will cause the condition Alan described. I call it the obligatory wrist crack/break. The break it's one of the easiest to repair. If the old gun is not a collector the stock is usually available on Ebay for $40.-$50.I don't know how much you shot it or if you shot it at all. It cracked there for a reason. There was probably a lot of stress at that point. I'm surprised the tape held it together. I wouldn't feel comfortable shooting it and breaking my cheek or losing an eye.