[bill larry]

Anyone know the differences between the Model 17-3 and the 17-4?

Are the cylinders and barrels interchangeable?

Thank you!!

[Ron James]

-1, 1957 Change extractor rod from right to left hand thread
-2, 1961 Delete trigger guard screw,change cylinder stop.
-3, 1967 Relocation of real sight leaf screw..
-4, 1977 Change to move gas ring from yoke to cylinder.
So, there is a difference between the -1,-2, -3, and -4. The -4 has the gas ring on the cylinder , the -3 has the gas ring on the yoke.

[zt77]

what is the gas ring and what does it do?

[MountainBear]

The barrel and cylinder should be able to interchange if they are fit properly.

The barrel will need to be indexed and have the gap set between the barrel extension and the cylinder.

The cylinder will need to be fit and timed. I believe all the rimfires were recessed cylinders, so it should be fine.

But its going to be an expensive proposition to have these parts refit to a revolver...