That is the "man with no name conversion".
http://www.cimarron-firearms.com/Con...NoNameConv.htm
It's a copy of one of the guns Clint Eastwood used in his "spaghetti" westerns. It's not really a "conversion". It's a .38 cal 1872 open top revolver with a 51 navy barrel. The 51 RM conversion is a replica of an actual 19th century revolver.
http://www.cimarron-firearms.com/Con...ConvOpener.htm
I like both of them, but I like historical guns a little better than movie guns.