I stoped at a garage sale today and the guy had some rifles and some misc. Ruger Blackhawk parts. One was a cylinder .357 mag that he said came from a Blackhawk. It did look like a BH cylinder except the rim of the .357 case was counter sunk into the face of the cylinder and there was a 1/8" to 3/16 wide grove cut all the way arround the cylinder, I would assume to allow the cylinde to rotate if the firing pin was sticking out some. The ratchet on the cykinder did not extend as much as normal, but if you removed the recess for the case rim it would look like a normal cylinder. Did this type of cylinder ever come with any Ruger B.H. The rest of the parts were Ruger B.H. parts.