The Cimarron R-M conversions and Open Tops are made by Uberti. They are made considerably better than the Cap & Ball guns, both in fit, finish and steel. I have been shooting Open-tops in 44 Russian (They are actually chambered in Special & Colt, the Special chamber will shoot all three) . i have been shooting them with smokeless powder. So far they are sturdy enough for the job, but some say they should be used for Duelist class as the cocking action is gentler than a two hand operation. They benefit greatly from Wolff springs, and I replaced my hand spring with Ruger coil and plunger. The 5-1/2 inch barrel comes with a Navy sized grip, the same as a SAA, and the 7-1/2 inch barrel comes with an Army sized grip (1860 Colt Army). I would expect the 1872 Open-top to be a sturdier gun than the R-M, as the R-M has a shorter breech to screw the cylinder pin into, and has less parts, as the 1872 has a solid breech without the conversion backplate. If you want to shoot a lighter load, get the Opentop in 38 Special. They are offered in 38Special, 44 Russian, 44 Colt, 44 Special and 45 Schofield. Finishes are blue with Color Case and Nickel.