https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=609802

Flues Grade 1

[Linked Image from photos.smugmug.com]

The only thing that saved the gun was that the bullet was much smaller than the bore, and the gun recoiled freely. I'm amazed that it still locked up afterwards! The wood was missing from the top left before the shots.
Factory .50 BMG cartridge runs about 55,000 psi.

Scroll to 5 min.