I have a couple of 58's , a 60 , and a Dragoon. I liked them fine aside from the reload times I actually don't care much for the 60 but it is there .
My understanding of the cartridge conversions .
The cylinder with the firing pins is still a C&B .
The cartridge conversion with a true cartridge cylinder and a loading NOTCH typically located about 4:00 on the right side is still a C&B .
The 1875 and any alterations that fit a loading GATE to the arm , any of the pre 1873 Colts and the pre 1875 Remingtons (clones because a pre 1899 isn't ) are now and or manufactured as real guns .
I owned once a grey area arm . It was an 1873 SAA with a gate complete with the 4 clicks and the second notch gate release that was manufactured as a C&B . I had it about a year and tried really hard to love it ........I just couldn't do it . I never even figured out what I didn't like about it .....
Back on track , measure whatever you do my brass 58 44 Army has a .426 bore and .440 groove . Not really suitable for either a 44-40 or a 45 Colts , even if it were a steel frame .
The 58 in 36 cal would make a lousy 38 Special but an acceptable 38 Short or Long with a .35?×.361 barrel . Both 58's are Piettas
The Dragoon follows but is closer to a .445 groove with .448- chambers , it's a 70's vintage ASM .
The 60 Colts is doomed to just sit around looking good as it's missing a couple of parts and ASM isn't around anymore. Unfortunately mix and match doesn't work so I hold out to find a parts gun or some one that needs my parts more than I do . It does have a .450 groove and .450+ chambers .
The Italians are all under the Beretta roof now so there is some hope that parts and dealer services will continue for a good long time .
I know a little more like axle to barrel shimming for proper fit and cylinder gap . Not really important now so that's about it .