Variations on M610 cylinders?

[wizard.mk18]

I found a brand new M610 cylinder while cleaning and organizing my parts drawers.

This one is fluted. Is it possible to identify which M610 version would be correct for this cylinder?

To put it simply, are there more than two types of M610 cylinders, fluted and non-fluted?

 

[Kernel Crittenden]

In 1990 & 1991 the no-dash 5-inch gun, 103578, was fluted. So was the no-dash 6.5-inch 103576, in 1990 & 1991. Later, the -1 6.5-inch guns I saw were fluted with the same p.c..

 

[tlawler]

I just stumbled across this thread when I was getting ready to start a new one asking about M610 cylinders, so I don't think I'm really hijacking it.
I just purchased a new unfluted cylinder from another member on the forum. When I got it, I couldn't wait to swap it out. I finally got around to it today after receiving it on Friday. Disassembly and reassembly went smoothly, until I tried to close the cylinder. The new cylinder came with it's own extractor star, which has a deeper ratchet than the old one, so it would not allow the cylinder to close. I tried using the old one with the new cylinder, but the shafts are different. The older shaft has a notch, like a full length keyway, whereas the new one has a flat side. My 610 is a no-dash with serial # BFA7XXX. Does S&W sell extractor stars with different depth ratchets to allow swapping of cylinders?

 

[wizard.mk18]

I think you just reminded me why I have a brand new 610 fluted cylinder. I purchased it many years ago as a swap for my un-fluted 4" model 610-3 and then discovered that they do not swap without doing additional work. I never took the project any further and put the cylinder into the S&W parts drawer, where it has now slept for the last 10+ years.

It appears the cylinder I have has the full length keyway type shaft and was an earlier design.

I wonder if I could lay my hands on a correct vintage N-Frame and do a caliber swap to 10mm?