J frame cylinder fitting

[nksmfamjp]

If a person has a new revolver and would like to fit an additional cylinder, is any fitting required?

I'm guessing both cylinder and revolver were made within the last 5 years.

 

[326MOD10]

I know that when I had a cylinder cut for 9mm it had to be set for timing with the revolver.

It was not the original cylinder from that handgun.

 

[310Pilot]

Yes, it will need to be timed and fit for proper alignment relative to the barrel. If fitting as an interchangeable cylinder, all the fitting and adjustment must be done on the cylinder star, as alterations to the hand will throw the original cylinder out of time. Not a drop in fit.

 

[nksmfamjp]

Any guesses on pricing?

 

[JDinAZ]

For the current style production. You may not have to do anything but put the cylinder in. And just verify it carries up and the cylinder stop engages before the hammer drops (this is checking timing).

I have a handful of j cylinders that will just drop right in and timing is fine on my 438. BC gap varies a shade but not out of spec.

Keep in mind the new cylinders should be the correct length. Right at 1.593 to 1.596 +\- range. That said. Older ones with the same style non pinned non symmetrical extractor star do exist and are about .060 shorter basically the same length as the old model 36 and 60 symmetrical star cylinders. Those are too short for the new j frames. Also. The round symmetrical ratchet and new non symmetrical ratchets are not interchangeable.


To check timing with no ammo in of course.

Put your non firing hand thumb on the side for the cylinder with light pressure

With your firing hand slowly in a controlled manner squeeze trigger.

While keeping that light pressure on side of cylinder.

Cylinder should carry up and lock in on the cylinder stop before the hammer drops.

If it doesn't go far enough to lock in you have a problem with the carry up not going as far as needed.

Or if it locks in and is difficult to finish the trigger pull then it carries up too far and that's a problem also.

Don't forget to check the BC gap (barrel cylinder gap) the new SW spec is 0.012 you need it to be smaller than that. The smaller the better as long as the cylinder turns and doesn't drag on the forcing cone.

 

[Hondo44]

Most similar vintage cyls will work fine. But you'll want a replacement cyl with it's own extractor star to avoid a lot of fitting headaches.

The most common fitting needed is the length of the cyl center pin and/or extractor rod to properly lock up under the barrel.

 

[steelslaver]

I agree that they often work. I run into the yoke tube being a bit long or short more than anything else. Fairly easy to adjust then the ejector rod length being a little off. I am actually amazed at how often the timing is alright.

One thing I have discovered is the old style extractor stars seldom go from one cylinder to another because of the alignment pins. They must have match drilled the pins as they seldom line up right. Plus, their location changed over the years. You can do 2 things if you want to do this, If the pins are just a bit off, fill the chambers with fire brass with star in place and drill the holes out just a bit over sized, then use the shank of the drill to make 2 new pins and secure them in cylinder with red Loctite. Or go to another location and make a complete new set of match drilled holes.

The new style ones with the odd tips on the arms seam to go from one cylinder to the other OK.

 

[JDinAZ]

I agree that they often work. I run into the yoke tube being a bit long or short more than anything else. Fairly easy to adjust then the ejector rod length being a little off. I am actually amazed at how often the timing is alright.

One thing I have discovered is the old style extractor stars seldom go from one cylinder to another because of the alignment pins. They must have match drilled the pins as they seldom line up right. Plus, their location changed over the years. You can do 2 things if you want to do this, If the pins are just a bit off, fill the chambers with fire brass with star in place and drill the holes out just a bit over sized, then use the shank of the drill to make 2 new pins and secure them in cylinder with red Loctite. Or go to another location and make a complete new set of match drilled holes.

The new style ones with the odd tips on the arms seam to go from one cylinder to the other OK.

Right

Speaking of the old style pins in the star. I just had that conversation with an old friend back East earlier in the week He's a decades long competition revolver shooter. We were measuring cylinders, his current in an old style model 60 and one that I had here (Already shipped now) that I already machined for my CCW HD moon clips so he could run it in his 60.

That's when he got to talking about the pins alignment thing. Said that there was a reason for it. He ran into that years ago and talked to Smith about it. They let him know it was an intentional change that was done in conjunction with engineering changes.