This to me is a example of often heard comments about poor stocks as the grain appears to run crossways across the lock area.
To my eyes it will never be a high value gun but if it is repaired so that will be something to shoot, hang on the wall and handle without fear of devaluing, I would repair it, if you have the skill.
Gary, one other thing would be to undercut the stock where the face of the barrel and tang are a 1/8 inch ta give some thickness to hold the barrel and run 1,4 inch dowel length way of the wrist between the tang and the left side of the stock it needs all the help it can get with it having the grain that has.
I hope you will diagram your suggestion, because I can't see it in my mind's eye, and I don't think we should assume our original poster can visualize it, either. No offense meant! I'm just asking for clarification.
With regard to other previous suggestions, as they come to mind...
Hide glue: It's great, it's historic, it absolutely does not creep under tension. Is it shock resistant? I don't know. I DO know that it is often described as "hard as glass." Hot hide glue is the absolute glue of choice for the stringed instrument maker. It will withstand constant tension from strings tuned up to pitch. But could it withstand repeated sharp impacts, such as a recoil upon firing? Instrument neck joints often fail when the instrument is dropped. YIKES!
Tight Bond: If I knew for certain that the cracks were free of dirt and other contaminants, I would consider using original Tight Bond. I would be sure I had a fresh bottle, too. I stress the word "consider." I have used Tight Band lots of times. I built a very nice custom archtop guitar with tightbond, and also a very fine tenor banjo, multiple mandolins, etc. etc. It is good stuff. It can creep in ultra slow motion, but I don't think it will shatter like glass upon recoil. I am not arguing with my buddy,
@Booner as I write this. We often disagree on ways to solve problems, but we always help each other out, and we ALWAYS get the job done!
Accraglass: I have seen it highly recommended on gunsmithing and repair sites. I have seen it work. But it is NASTY to clean up. Of that much, I am certain!