Hi Flatgate; Don't know if cylinder will fit or not.It may just drop in but I never tried it because the gun is new and 38-40 cylinder I bought later. I just bought it to make the gun back to convertible with both cylinders. Now I have a gentleman who wants to buy it and he needs to get the cylinder properly tuned and fitted or he won't buy it. I don't have the knowledge to be sure that it fits properly, so we're trying to find someone who could work on it to make sure it is right. Thanks, Jim
