Tracy, The Ribauldequins were built in Europe during the 15 and 1600's. I'll post some video of some tomorrow. I believe these type of guns were anti-personel defense weapons.
Douglas, The barrels are mounted parallel. Listening at the video closely, I think it's possible that since barrel #3 and #4 went off almost simultaneously, the muzzle blast from #3 may have caused the round from #4 to divert. I will measure the other shots on the target tomorrow to see if there was any convergence in the pattern. When I get a chance, I'll take it to the range and try some more shots. This time with more powder, 50 instead of 25 grains of BP.