Hi Guys, My buddy asked me to help him with a cylinder he inherited. It's a Single Six cylinder, like new, no turn ring, in its red pouch and white outer box (a bit yellowed). Serial number 21-557XX. I think that puts it in 1973. What I don't know is which cylinder it is. It is recessed for rims, no relief ring for the firing pin, no external roll-engraved indication of caliber. I do see an indication of a "throat" in each chamber. The "last three" of the serial are on the face of the cylinder. No wear on the front boss or rachet, so I don't think this cylinder was ever used. Can you folks give me a fair idea of price and which cylinder I am dealing with here? Many thanks and God Bless, Marc