Slamfire...WOW WOW WOW.
I am both happy and shocked at what happened to your father's WWII M1 piece. Happy that he was virtually unharmed and that it served as a healthy lesson....and shocked at what DID happen!
Lesson learned, dont trust old ammo thats been poorly stored for over 60 years. I dont plan to keep handgun ammo on hand for that long though