I can't be 100% sure, but I would bet the catastrophic blow up of the S&W was due to a missed powder load followed by a shot with the first round (bullet) stuck in the barrel. That or a double charge of powder in the second cartridge. I didn't get to examine the pistol but it appeared the barrel, top of the cylinder, and top strap were split. The first round the man fired did not sound right to me, but I had earplugs and muff's on so I can't be sure. They were his reloads so of course he's not going to admit he might of screwed up.