What do I have here? It's a S&W Model 66-1 serial number 43KXXXX made in 1978 or 79 with a unfluted cylinder that has fingers for a 9mm conversion. Anybody know who might have made this and what it might be worth?
The Medusa folks made conversion cylinders as well as multi-caliber revolvers. I think that is what you have here.
Try some different cartridges, it is supposed to take a wide variety in the 9mm-.38-.357 series.
Worth? I don't know. Are you buying, selling, insuring, or what?