Rino

For your stock to have cracked at the tang, the tank itself was probably acting as a recoil lug bearing on the in-letting at each firing. There should be a small space carved out behind the tang. Also the rear-most action screw hole should be drilled out enough that the screw is not bearing anywhere on the stock. You want all of the recoil force distributed onto the recoil lugs - and nowhere else.

Pat.