You need one from before, about, 1958, or something like that. You
need one for a 5-screw frame, not a 3-screw frame.
If you have a micrometer, measure the width of the piece that protrudes through the frame and into the cylinder. These are typically
slightly different widths. They vary by about .003 to .005, from thinnest to thickest. If you get one too thin, the cylinder does not lock up very tight, but can be rotated slightly.
Second thing is that they typically need some fitting. There is a timing issue about when it gets pulled down by the trigger, so that that the cylinder frees up, and can start rotating.
Generally, if you use an older one, from an older gun, they tend to work without fitting.
I have some extra ones . I need to know what width you are looking for, and I have to come up with a price !
Later, Mike Priwer
[email protected]