I'm I correct in assuming this is from a Vaquero revolver? Maybe a Blackhawk? I think the cylinders were interchangeable anyway but not 100% on that. I don't have any Vaqueros or Blackhawks anymore so can't compare in person. It's for sure a 9mm conversion cylinder as a 9mm drops in perfectly and there is a step in the chambers to hold it. 38 or 357 ammo won't fit. There is a stamped S on the rear and 946 on the front of the cylinder. Also-any idea of it's value?