A heck of a blowout!

[Dean Romig]

Looks like the result of a double powder charge.





.

[Drew Hause]

Or a powder substitution

A 3 Dr. Eq. load of “E.C.” No. 1 or “Schultze” was 42 grains by weight. Upon introduction, 3 Dr. Eq. of Dense Smokeless Ballistite was 24 grains; Infallible 22 grains. (Later the powders were equivalent)

Substituting a Dense Smokeless powder for Bulk Smokeless powder would double the charge. It has been estimated that 50 grains of Infallible or Unique could reach 30,000 psi - which is where Bell's damascus and Vulcan barrels ruptured.