The Ruger Old Army is probably the "best" percussion revolver ever built and shooting it as a cap-n-ball revolver with black powder is a blast. However, on occassion, it's fun to have preloaded .45 Colt black powder cartridges ready to shoot and putting them through a ROA is also fun. A while back I made a video specifically to educate those who were curious as to how you load and shoot .45 Colt through a ROA via a conversion cylinder.
Obviously, this isn't for everyone and I certainly understand why some folks think it would be odd because you can purchase a ready made revolver to shoot .45 Colt cartridges. And, a lot of these folks might also question why anyone would bother to reload cartridges because you can simply purchase them off the shelf. I get it. But, the answer is "....the spice of life..."
https://www.youtube.com/watch?v=I5AwhP9yzKk