Yes
the most popular is with modifing the rememgtion modle with the top strap. The cylinder can be replaced with out breaking the gun appart, IE pull the hammer back, pull the loading handle down remove the cylinder pin and replace the cylinder.
If you want to know how they work, watch the movie with Clent Eastwood called "Pale rider"
To modify a colt bassed gun it VERY expensive. Replace the hamme, the cylinder, then machine the rear part of the receiver to open on side of the cylinder then add a spring loaded (not sure what you call it) door that allows you to load the gun with out removing the cylinder.
After the civil war with cap and ball guns so cheep and when the colt peace maker came out, it was so expensive that many people couldnt afford one at (if memmory serves me) 25$ where cap and ball pistols could be had for a couple of dollars a lot of mods took place.
Again to agree with what others have said, if you decide to do this, I wouldnt even fire cowboy loads through one. Most built are of a softer steel and are made for black powder. The gap between the cylinder and barrel breach is often larger to keep fowlling to a minimum and allow the cylinder to keep turning even after firing many rounds. If you start shooting smokless with the much higher pressure rates and tempature it will start cutting into parts of the gun like the top strap in the rememgtion or the cylinder pin in colts.
I dont know what your reasions for asking the question, but being a C&B collestor (14) there messy, there durty, hard to clean, slow to fire, not that powerful, not that accurate, but for bang for the buck there are few guns to give as much fun.
Go to a cowboy shoot (CAS) and shoot against a bunch of people shooting colt nickle peace makers with a cap and ball black powder gun and see the reaction. You tend to get a crowd following you around.
