Looks like when whoever put the recoil pad on forgot to drill the old timber first & it split from there.

Would you have to spread the cracks & epoxy as well as dowel from underneath? Otherwise your next option will be a restock & refurbish to bring the old girl back to her full glory.
You still have a marvellous old rifle there Casper, even if she's showing a bit of wear & tear she still looks bloody grand to me!

Don't forget to let us know about the loads also please!
Regards