Trying to repair a crack, helps by understanding how it happened.
A fall, wood stress grain crack, or recoil related.
With today's good wood glue, a proper repair will make it stronger than ever.
If you can carefully get the glue to seep into the crack, and then squeeze the wood together for cure time, all will be great.
Sometimes you must gently pry open the crack and get the glue to flow into the crack.
Sometimes you can use a vacuum cleaner to suck the glue into position, or compressed air to push the glue into position.
However you must do it rather quickly as the glue cure time is rather fast.
Once again after you get the glue into position, you must squeeze the glue joint together as best you can.
Leave the stock alone for twenty four hours for best results.
Be shure to use the carpenters wood glue, not Gorilla glue or the super glues, they don't work well in these applications.
Best regards
Old Ford