if Colonel Colt had gone the step to breech loading cartridges a little bit earlier he had avoid the chain fire problem. here you have a revolving carbine by Lefaucheux in Paris Mod 1858

http://www.galeriedemars.fr/allfolks/CFA2007_frameset_UK.html
65 cm long barrel, shoot the long 12 mm Pinfire carbine cartridge

such revolving carbine had have some popularity in the 1860s
here is a Liege made copy in 10mm pinfire in the next Hermann Historica auction

http://www.hermann-historica.de/db2_de/onlinekatalogeneu/schusswaffenneu.html