1917 cylinder swap?

[willy]

Will a 25-5 cylinder swap with a S&W1917 cylinder?..

[murphydog]

According to the standard reference book the 1917 cylinder is 1.55" and the model 25 1.53". Don't know if this is significant or if there are other differences between a pre- and post-war cylinder that affect the fit.

[cgt4570]

Yes. There may be significant gunsmithing involved to set barrel-cylinder gap, headspace and timing, ejector rod length, etc. I fitted a 625 non-fluted and a 625-10PC cylinder to 1917 and 1937 project frames respectively. Also, the original ejector rod won't fit in the newer cylinders. Opposite threads. If you have the time and skill, it can all be done (carefully) with hand tools.

[WR Moore]

One thing not mentioned above is to make sure that the newer cylinder actually bottoms on the yoke barrel to establish headspace/ end play. There may not be much, if any difference, but you need to check to be sure. The later N frames are similar to the older ones, but not identical, even if they still have the locking bolt on the barrel.

I once ran into a 28 converted to .45 where a famous gunsmith shop didn't check this and the cylinder was using the gas ring to locate the cylinder fore and aft. The gas ring was never designed for that (George Nonte's mistake in at least one of his books.). I had to make a spacer to take up the difference between yoke barrel and cylinder. IIRC, the difference was almost 1/16".

[41 fan]

One of my 1917's measures 1.53. One of my 25-9's measures 1.67. Dean

[steelslaver]

All the 4 coolt cylinderrs except the 25-3 are about .10 inch longer than the acp cylinders, plus about .035 on the rear for the moon clips, so if refitted frame lug must be modified also so rear of cylinder with not hit when opened