N-Frame cylinder question

I have a 629-6 and the cylinder rubs on the back of the barrel when closing and there's no gap between the cylinder and the back of the barrel (cone?). I have turned the cylinder six times when closing it and it rubs every time. (Please forgive my terminology, etc., as it's early and that's my excuse for now!) there is a very small amount of cylinder play back & forth and if I push it back it doesn't rub. I was wondering if thin shims (.001) are made to put between the extractor rod and the collar? I have an extractor rod removal tool on its way from Brownells. I was first going to unscrew it a little, spray some quick evaporating cleaner (circuit board cleaner I used when I was still working commercial HVACR service) on it and screw it back in before I do anything first in case there's a tiny something in there.
Or, do I take it to a gunsmith and let him/her do their magic? The cylinder turns fine when I shoot it, dry-fire it, single or double action, and it doesn't spit anything out the side when I shoot (probably because it's so tight between the two areas.) I bought the gun used before end of 2020, but I don't get it out to the range very often, so I just recently noticed this. I did have a couple light strikes in double action (maybe 5 at most) shooting .44 Specials, but I found the tension screw wasn't turned in all the way. Any thoughts, etc., appreciated.
Thanks, Jeff T.

You can buy endshake shims, but they must be properly installed. Since you have a new-production 629, I’d probably just send it back to S&W, if it were my gun. The shim goes between the yoke and the cylinder. The face it is seated against in the cylinder must be clean and sometimes both parts, yoke and cylinder, will need to be squared up for the assembly to turn smoothly. I’d just let S&W fix it.

Let a gunsmith tune it for you, or if new send it back to S&W. When you say it rubs, is it a consistent rub (each and every charge hole), or is it only at one spot around the cylinder? If only at one spot, it indicates either a bent yoke or an improperly surfaced cylinder. If it rubs all around and end shake is within spec, the barrel/forcing cone may be set too deep. The cone to cylinder gap should be around 0.040".

There are shims called end shake shims. But I think the thinnest is .002. You really should check your end shake before proceeding. Get a set of feeler gauges at any auto parts store and moist hardware stores. They are thin leafs of spring steel and should at least read from .002 up. You are really only interested in .002 to .012. Knowing that your cylinder touches the barrel we know that your forward measurement is 0.000. Now press the cylinder to rear and find the smallest gauge that will just slip between barrel and cylinder .004 to .006 is ideal. I try to shim so I only have .001 end shake. You do not want cylinder to tight on yoke barrel as it need some slack to rotate free.

If the gap between barrel and cylinder is under say .003 with cylinder pressed back against recoil shield as it should be with shims to achieve minimum end shake, you really need the barrel end trimmed to achieve this. There is a tool for this, but it can be done with a file that has had teeth removed on the sides. But, you must know how to run a file. Barrel straight down in padded vice. File held dead flat on barrel end and kept flat and level during every stroke. Stroke only in direction that file cuts, reposition steady stroke, reposition. DO NOT ROCK FILE.

The tool is available from Brownells
cutter- BROWNELLS 90^0 CHAMFER CUTTER | Brownells
basic kit to use with cutter- BROWNELLS 90^0 CHAMFER CUTTER | Brownells

But, the cost of those is more than the cost of a gunsmith,

Also, you could probably send it in to S&W for repair

PS. a bent yoke will NOT cause the cylinder to hit in one spot and not the other. As the cylinder turns on the yoke barrel and as the yoke barrel does not move any misalignment of yoke will cause the cylinder to be consistently misaligned as it turns on yoke tube.

The proper term for the barrel sticking though the frame in this area is barrel extension. People often call it the forcing cone, but the forcing cone is the taper inside the barrel extension. The gap is between the cylinder and barrel extension face.

Occasionally you will find a cylinder that is slightly out of square. But normal end shake should be more than that. I have yet to see one that was .002 out.

Give it a good cleaning first. You can get the extractor rod out easily by using the chuck of a hand drill. Put the rod into the chuck just like it was a drill bit and turn it out by hand.

Vtgw938 said:

Give it a good cleaning first. You can get the extractor rod out easily by using the chuck of a hand drill. Put the rod into the chuck just like it was a drill bit and turn it out by hand.

Click to expand...

Left hand thread. Dirt and debri under ejector star can cause the B/C to close up IF there is excess end shake. It can also be build up on the face of barrel extension or cylinder It is possible that the yoke screw is not holding yoke all the way to the rear. Can OP get B/C clearance by pressing back on front of yoke arm?

Hair Trigger said:

The cone to cylinder gap should be around 0.040".

Click to expand...

Forty thousandths is way too much. It should be .005 to .006.

I do need a new set of feeler gauges, and I think the ones I have don't go down that low. If pulling out the ejector rod & cleaning it doesn't work, I have a guy. I really didn't want to send it back to S&W and wait. And wait. I really appreciate the help & information.
So, I take it I should NOT take my Metabo to the end of the barrel!!? I said as I ran my fingernails down the chalkboard!!

Hair Trigger said:

The cone to cylinder gap should be around 0.040".

Click to expand...

Might want to correct that?

jeffrefrig said:

If pulling out the ejector rod & cleaning it doesn't work, I have a guy. I really didn't want to send it back to S&W and wait. And wait. I really appreciate the help & information.

Click to expand...

You don't need a gunsmith and I too, would not send back to S&W for this minor issue!

As steelslaver posted, "Dirt and debri under ejector star can cause the B/C to close up". You don't need to remove the extractor rod to clean that area.

Then if the problem still exists, take your measurements and let us know what you find.

Metabo, no. Everyone knows that this is what the Dremel tool was designed for.

(OH god, please take this for the joke it was meant as.)

Believe me, I know that! But, it's amazing how bad my pipe vise can screw up the finish on a new Python!

Protocall_Design said:

Forty thousandths is way too much. It should be .005 to .006.

Click to expand...

Oops, put the decimal too far to the right. My typing fingers are dyslexic. Thanks for catching that.