our friendly gun smith checked and said it missfires because it has to much head space.
I have remedied this by sizing the cases to fit the chamber but I would like to fix it right.
PM me if you want to sell a stripped bolt head.
push a primer in an empty chamber with your finger take it out razor blade across the primer and a feeler gauge .003 max.
have you tried factory ammo.? does it also cause problems. did the gunsmith try a 308 no go gauge in it?