I shoot my 1849 Colt pocket, all original from 1863. You probably know all about the sighting being way up for short range shooting - they were sighted for 75 yards, a very ambitious range to get any kind of accuracy with this gun! You might find the mainspring has lost some of it's tension, causing the hammer to blow back a bit more than it should and blowing the cap or fragments of it into the channel in front of the hammer. I partly solved this by taking it apart and unscrewing the spring slightly, then putting a sliver of metal like a wedge where the screw holds the spring and retightening it, slightly increasing the angle of the spring and its tension. Another cause of this problem is enlarged holes in the nipples, causing more blowback than should happen. So far, I haven't managed to remove the nipples - tried solvent, heating, etc - and have opted to leave them in for the time being and live with it. I've only been loading and shooting a single chamber at a time, because I think the slightly increased blowout of fire from the nipple - vividly seen in night time photos! - probably slightly increases the chance of chainfire, which can happen via the nipples especially if the caps are not well seated. Just a few quick thoughts. It is great fun though to shoot, and a labour of love with all the cleaning involved - I've got it down to a mere hour and twenty minutes, but what better way to spend an evening!