Our old friend Flatgate tried to send me a FA (scrap) cylinder long ago to do this with. Sadly,, the mail service damaged the package during shipping & the cylinder was lost. I wish I'd been able to get it. Thanks anyway Carl!
I saw one of those on the desk of one of my best customers many years ago. Fortunately he didn't know what it was and let me wheedle him out of it once he heard it was a gun part.
Turns out it was a complete cylinder for a Colt "New Service" .44 Special DA revolver and I had a NS with the barrel marked "New Service .44 Russian and Special" that lacked a cylinder. Still have the completed revolver!
Things like that don't happen often, especially to me.