barrel didn't. I'd point to metalurgy primarily. SOMETHING had to come out of the barrel.

It's not hard to do a double charge in a reload, but it is pretty difficult. 17gr of powder is a significant bulk, then the wad then the shot. SHOULD have spilled some shot out, or been very very difficult to crimp. Wads don't compress well. But if doubled, the load itself would have been compressed tightly and given a greater pressure spike enough to damage a gun.

But just looking at the chamber as the failure point, without barrel involvement from the photos shown, I'd say defective metalurgy. There is this gigantic hole that would have vented a double load (12ga) pretty effectively.

I'm guessing this is one of those cheaper imported O/U's - you get what you pay for.

Ouch!