contrary to what you guys are saying about nipples I actually experienced several chain fires when I was a teenager. once I got all six off in one shot. It was absolutly from loading real BP as much as I could get in the chamber and still have the cylinder turn with the ball seated and then forgetting to lube. back then i used vasaline because thats what the guy at the gun store told me to use. 1977 ish.. that was my standard load and it only chain fired the few times I forgot to lube. lead smeared all over the barrel and loading lever. rather exciting.