So, what was the logic behind Ruger's move? My guess is that, originally, they saw an opportunity in the Cowboy market and only had to do a minor retool to their existing line of frames/guns to accomodate it; but, more recently, they've seen enough of a response in Cowboy-land to warrant a complete separate line, albeit a little smaller-framed to better match the "real" (i.e., original) cowboy guns. Also, cowboy shooters didn't necessarily need the strength of the larger-framed guns because they weren't shooting hunting-strength loads.