How to fit a cylinder?

[Kilroy08]

I had an old S&W Victory Revolver fall in to my lap the other day, hooray!

Not so hot was the fact that it was an old lend lease gun that was converted. It's a Cogswell & Harrison deal where they just punched out the cylinder for .38 Special with a blatant disregard for the chamber size of the original .38-200.

I was debating scouting around for a used .38 special cylinder or picking up a replacement on from Midway.

How do I go about fitting the new cylinder to the gun? Yes, I could pick up a used Model 10, but I do enjoy a good project.

I'm a bored machinist who loves to tinker in my spare time. I have done some gunsmithing in the past, but fitting stuff for a revolver is a new experience for me.

 

[Dfariswheel]

Here's a short primer.

You need a cylinder and ejector ASSEMBLY.
Cylinders head space on the ejector so fit you fit an ejector to the cylinder then fit the assembly to the frame.

Once the ejector is fitted to the cylinder (the ejector lines up with the chambers with no overlap and seats fully into the cylinder) the rear of the ejector is precision surface ground to set head space.
If the ejector is a used one, it may be too short to be fitted to the gun. Even if the ejector is original to the gun, the cylinder isn't and things change.
A short ejector is unusable because it can't be stretched or made longer.

With the head space set the cylinder is installed on the yoke or crane and it's test fitted into the frame.
The cylinder is checked for proper end shake, which is to be minimal. (End shake is back and forth movement of the cylinder in the frame).

In reality, what you're doing is fitting the cylinder assembly AND the yoke at the same time, since the cylinder has to be on the yoke to set head space.
This is a matter of test fitting the assembled cylinder, ejector, and yoke into the frame, deciding what needs to be altered just enough to get it in, then setting head space and adjusting end shake.
This is sort of a one man band trick.

If the cylinder won't snap into the frame, the yoke barrel is trimmed until it will.
If the closed assembly has too much end shake, the yoke is either stretched (factory method) or hardened stainless steel washers are installed into the cylinder to set proper end shake.

Next is to check chamber/bore alignment on all chambers with a range rod.

Then timing is checked on all chambers.

For fuller details, buy the book "The S&W Double Actions Revolvers: A Shop manual" by Jerry Kuhnhausen. This was a training aid for new gunsmiths and shows in detail how cylinders are fitted and adjusted.

Note as above, that used parts may or may not be usable at all and S&W parts did change over the years.

http://www.brownells.com/books-vide...the-s-w-revolver-a-shop-manual-prod25717.aspx

 

[Kilroy08]

Thank you very much! I'm always glad to have an excuse to add a new book to the library.

The Cliff's Notes are greatly appreciated, thank you again. Looks like I have some reading to do.

 

[James K]

The best solution to that problem is just to go ahead and shoot the gun with either cartridge. The difference between the base diameters is not enough to worry about.

Jim

 

[Kilroy08]

While it has all the proof marks approving it for .38 special use, the oversize chambers would still goober the brass in such a manner that I would not want to reload it.

Since the gun has already been altered, thus killing the collector value, I wouldn't mind using it to hone my gun smithing skills.

 

[James K]

I have fired I would guess a dozen or so of those guns and never had .38 Special brass expand much more than it did in some .38 Special chambers, and it reloaded OK. (The SAAMI specs for the two cartridges overlap.)

Still, if you want to install a different cylinder, please read and heed what Dfariswheel says; he knows whereof he speaks.

Jim