Well, the conversion for a ROA is an easy one really. It's just the natural progression of the black powder era. Just like my Dragoons, my Army, Remies . . . . . I personally like the arrangement of the conversions the most. Old world beauty/elegance meets modern "no muss, no fuss" . . . . . .
I really feel like it's the best situation for me
Likewise, a converted ROA is a natural. The best cap gun ever produced can indeed be "converted" into a top performing cartridge gun!
The whole idea about the "expense" of the conversion cylinder, that some like to use as the excuse for not getting "into" the conversions, is silly! Unless you buy used, you'll spend more money buying a complete cartridge gun than the conversion for your cap gun. BTW, used conversion cyls/ gated conversions can be had too, I have no problem with saving that way . . . . . it goes both ways .
As far as .45acp being used in a revolver cyl. chambered to fire it, the "free bore" is just like any other revolver made to shoot a rimless cart. My El Patron shoots .45acp as well (if not slightly better) as the .45C it originally came with. The ROA should be no different. If one has a ROA with conversion cyls, they have the best set up you could ever have as far as strength/durability/action parts. The strongest cap gun ever made is easily the best platform for whatever cylinder would be made for it. 45acp is a walk in the park . . . . . . .
Mike