Damn, that took a serious chunk out. I didn't notice the big crack behind it at first.
No pics, but I was with a friend at a small VFW gun show last year, and he bought a nice black powder kit gun that was all built. The guy told him that it had a ball jammed in the barrel. He got it for a steal, took it home, was able to dump powder out of it and poured water down inside before drilling (slowly) by hand with a bit through the ball that was inside.
He got the ball out and found that it still had something else jammed in there, and it turned out to have some kind of "cartridge" as he described it shoved in it. He got it out and said that had anyone tried to fire it, they'd most likely have had it blow up in their hand. I'm glad he knew what he was doing and some dumbass didn't get it and try to fire it to clear it.