Chain fire seldom if ever occurs at the cylinder mouth. It happens when you use too large a cap and pinch it or NO cap, across the nipples. My first BP revolver was an original Navy .36,the nipples were burnt out to near 1/8". Didn't know my butt from page four, so I used the load Elmer Keith recommended in "Sixguns",--all the powder you could stuff in and still seat the ball. Threw a gallon can onto wet ice in a field, lined up nd touched her off. Brrrrack!! Six splashes near the can! Gas squirting from those huge nipple holes blew the hammer back and rotated the cylinder, the trigger was still pulled so it fell again--repeat, repeat. The World's first fully automatic, gas-operated percussion revolver! Interesting, but hard on the underwear. From what I have read, a bullet will always be more accurate than a ball, so, not satisfied with the accuracy I have been getting with my ASM 1861 Navy I am in the process of making a bullet mould. I have already smoothed out the forcing cone and slicked up the action some.I have been lubing with a 1/8" felt wad soaked in a bees wax/olive oil mix with a thin card wad to protect the powder. I was very impressed by an ad for some paper cartridges where a guy using then ran 4 cylinders in about 5 minutes.Do any of you lads "roll your own"?