Cylinder Dragging On Forcing Cone

[zip308]

The cylinder of my 625 is ocasionally dragging on the forcing cone on two cylinders. Do I have somthing bent? The gun is pretty new with maybe 2000 rds through it and hasnt been abused. The weird thing is that it is not consistent. Sometimes it will do it sometimes it wont. The gap is pretty tight on all six chambers. It has done it some since it was new. Is there something I can do myself or should I just shoot through it until the end of the season?

[10mmdave]

The cylinder of my 625 is ocasionally dragging on the forcing cone on two cylinders. Do I have somthing bent? The gun is pretty new with maybe 2000 rds through it and hasnt been abused. The weird thing is that it is not consistent. Sometimes it will do it sometimes it wont. The gap is pretty tight on all six chambers. It has done it some since it was new. Is there something I can do myself or should I just shoot through it until the end of the season?

How's your end shake ??

I've had the same problem with tight B/C gaps and sloppy yoke shafts, end shake

has to be real good or B/C has to be real big

If you have end shake then maybe a shim will help, it will get that face of the cylinder a

little farther away from the barrel.

And to add a question for other's out there ......

I have 2 or 3 revo's that have had one of the bearing areas on the yoke shaft ground off ??

this adds to the above problem drastically when it's the rear "lobe" but still causes fit's when

the front one is removed. And I've only seen this on used revo's, not factory fresh ones.

Was this a S&W pistolsmith's fix for something ??

[spook]

I had the same problem. Gave me much stress on tight shots, because the dragging would screw up the trigger pull.

Use a shim and it worked like a charm

[Round_Gun_Shooter]

Another possibility is bent yoke or severely bent rod.

Regards,

[Keith]

Chad,

I may be able to dig up a shim from my bag of tricks if you end up needing one.

[Waltermitty]

Sounds like it probably just needs a shim or two.

You can get an idea with a set of standard automotive type feeler gages.

With the gun unloaded:

Push the cylinder forward (towards the forcing cone) and see what the thickest gage is that you can fit in the gap. Write this number down.

Pull the cylinder back against the frame as far as it will go and see what the thickest gage is that will fit in the gap. Write this number down.

You would like to see a minimum of about .004" to a maximum of about .006". You would like to see the maximum difference between the two number to be about .001".

"Like" is not the same as "must", but if the gap is much less than ~.003" you won't be able to shoot much before it starts dragging. It'll be perfectly fine when clean, but it won't run well dirty.

What I suspect you will find is that the first number is too low, the second number will be close or a little too big (~.007") and the difference will be ~.003" - .004". If this is the case, the next step will be to figure out where the slop is; it can be between the cylinder and the crane, or between the crane and the frame. When you get your measurements come back and we'll figure it out.

Note: When you do the measurements, try to see if the movement is in the whole crane assy (including the cylinder) or just the cylinder. If the whole crane is moving, check that front screw on the right side of the cover plate to make sure it's tight.

[cking]

My new smith had yoke cut at .003 off square. find somebody with a yoke reamer and some powers washers. I like two .002 washers with little lite lube, cylinder spins like it is on air bearings.

If you cylinder gap changes as you spin the cylinder something got bent which isn't as hard to do as you think in the heat of a IPSC match reloads.

[zip308]

"Like" is not the same as "must", but if the gap is much less than ~.003" you won't be able to shoot much before it starts dragging. It'll be perfectly fine when clean, but it won't run well dirty.

It does seem to work better if I get all of the fouling off of the front of the cylinder with a lead cloth.

Kieth,

I may need some help with this, I dont even know where a "shim" is supposed to go. Hell I cant even shoot a stage clean anymore... That Glock in my hand felt pretty good during that classifier on Tuesday. It may be time for an intervention, I keep having nightmares of steel not falling.

[Waltermitty]

My new smith had yoke cut at .003 off square. find somebody with a yoke reamer and some powers washers. I like two .002 washers with little lite lube, cylinder spins like it is on air bearings.

If you cylinder gap changes as you spin the cylinder something got bent which isn't as hard to do as you think in the heat of a IPSC match reloads.

This is the norm. No 625 is competition ready until the yoke is cut and shimmed. Let the shim take all the wear and tear. When the gap or endshake go back out, replace the shims and carry on. It's really the only way to go.

[zip308]

Sounds like it probably just needs a shim or two.

You can get an idea with a set of standard automotive type feeler gages.

With the gun unloaded:

Push the cylinder forward (towards the forcing cone) and see what the thickest gage is that you can fit in the gap. Write this number down.

Pull the cylinder back against the frame as far as it will go and see what the thickest gage is that will fit in the gap. Write this number down.

You would like to see a minimum of about .004" to a maximum of about .006". You would like to see the maximum difference between the two number to be about .001".

"Like" is not the same as "must", but if the gap is much less than ~.003" you won't be able to shoot much before it starts dragging. It'll be perfectly fine when clean, but it won't run well dirty.

What I suspect you will find is that the first number is too low, the second number will be close or a little too big (~.007") and the difference will be ~.003" - .004". If this is the case, the next step will be to figure out where the slop is; it can be between the cylinder and the crane, or between the crane and the frame. When you get your measurements come back and we'll figure it out.

Note: When you do the measurements, try to see if the movement is in the whole crane assy (including the cylinder) or just the cylinder. If the whole crane is moving, check that front screw on the right side of the cover plate to make sure it's tight.

Ok the front screw is tight, it seems like the cylinder is doing most of the moving but with the cylinder open I can get the crane to move a littel side to side. I get about .0015" when pushing the cylinder to the forcing cone and a max of .004" when pulling it away. If I need a shim, where does it go? I have had the cylinder and crane out but never removed the cylinder from the crane so I may need a little direction.

[cking]

Remove the front screw, open the cylinder, turn cylinder until the relief cuts align and allow the yoke and cylinder to slide out the front. Now you will need to unscrew the ejector rod. It is backwards threaded, so when looking at it, it unscrews clockwise. put some spent brass in the cylinder to support the star. Find something tough to wrap around the ejector rod to protect it from the pliers or whatever tool you have handy to loosen it. Careful about locking pliers it is easy to crush the tube. Unscrew it, now there are two springs a collar, that you need to pay attention to during disassemble. Also it is under a little spring pressure. The long bolt lock pin in there also note its direction.

Once it is apart you will be able to figure it out pretty easily. Now the washer and yoke part.

Take the yoke and cylinder and clean them inside and out. I just take my to kitchen sink and scrub them using dishsoap and hot water. Clean the inside of cylinder and yoke. Then dry them, hair dryer is fine.

Now take a black majic marker and on the end of the yoke make it black all the way around. Slip the cylinder over it and spin it a few times and remove. Inspect the end of the yoke to see if the black is gone all the way around the yoke end, or just part of it. If it just part of it the yoke is cut crooked.

Brownells sells a tool that will cut and square up the end . They also sell the washers that you put in the cylinder where yoke goes. I like two of the .002 thickness ones with little oil on them.

Now fitting. You can cut too much. Before you start cutting take some measurements. put the star ejector in the cylinder. put cylinder on the yoke and put the assembly back in the gun. leaving the other stuff off.

Hold the yoke closed with one hand at the front part of cylinder area. Now with other hand feel how much play you have not left to right but front to rear. so toward the barrel and toward the hammer. Don't confuse wobble of cylinder on crane/yoke with end play. Now push the cylinder forward toward the barrel and spin it. Does it hit the barrel? Was yoke test with majic mark showing only partial contact pattern?

Now time to cut, first just square off the yoke, cut, mark test a little at a time until you get even wear pattern. Now put one washer in put back in gun and test again for cylinder gap and hitting the cylinder. If it clears the cylinder with about .003 gap and a little endshake still exists your done. Unless you want to cut more off to install two washers. Do not remove all endshake when gun get hot it will bind.

One last little finishing touch. When you cut the yoke it will have some sharp edges. both inside and out. take alittle very fine say 600 grit wet/dry and just break the edges and remove the burrs. And if your really into it and have a dremel tool, I take a fine cratex and smooth the inside face of the cylinder also.

Why do all this, well it will let you do two things. The gun DA pull will be smoother, less work for hand to do. Second for what I call staged pulls. I can pull my trigger about 3/4 way back quickly and cylinder will spin all the way to lock, so that last 1/4 pull in not moving the cylinder and helps steady the gun for a fast accurate shot without going to SA.

I don't recommend that a beginner work on the star or hand, but it is a good time to check to see if the hand is binding on any of the cylinders. it will be in that last 1/3 of the DA pull as hand slips off the ratchet. If it is get a smith to fix that part, or live with it, it will wear in.

Now how to tighten the ejector rod? Same reverse process, some like a little loctite blue on thread of the ejector others hate that idea. Well I use just a little. not enough to cover all the threads, keep the parts clean and dry, even no hand oil. take toothpick and put the smallest drop on large end of the threads of the ejector rod and assemble. Oil after loctite has dried.

[Waltermitty]

Sounds like it probably just needs a shim or two.

You can get an idea with a set of standard automotive type feeler gages.

With the gun unloaded:

Push the cylinder forward (towards the forcing cone) and see what the thickest gage is that you can fit in the gap. Write this number down.

Pull the cylinder back against the frame as far as it will go and see what the thickest gage is that will fit in the gap. Write this number down.

You would like to see a minimum of about .004" to a maximum of about .006". You would like to see the maximum difference between the two number to be about .001".

"Like" is not the same as "must", but if the gap is much less than ~.003" you won't be able to shoot much before it starts dragging. It'll be perfectly fine when clean, but it won't run well dirty.

What I suspect you will find is that the first number is too low, the second number will be close or a little too big (~.007") and the difference will be ~.003" - .004". If this is the case, the next step will be to figure out where the slop is; it can be between the cylinder and the crane, or between the crane and the frame. When you get your measurements come back and we'll figure it out.

Note: When you do the measurements, try to see if the movement is in the whole crane assy (including the cylinder) or just the cylinder. If the whole crane is moving, check that front screw on the right side of the cover plate to make sure it's tight.

Ok the front screw is tight, it seems like the cylinder is doing most of the moving but with the cylinder open I can get the crane to move a littel side to side. I get about .0015" when pushing the cylinder to the forcing cone and a max of .004" when pulling it away. If I need a shim, where does it go? I have had the cylinder and crane out but never removed the cylinder from the crane so I may need a little direction.

The crane will move more when it is out, but that's not very important. The critical movement is the cylinder locked in the frame.

The cylinder assembly will slide right off of the crane when it is out of the gun.

As cking said you have to take the cylinder assembly apart. The threads are left-handed. There are tools that make this easier. I have done it with pliers but I've also boogered up some ejection rods.

If S&W was the last to work on the crane the end of it will be as rough as a dirt road. This is normal. I have purchased a reamer to square this up and smooth it out, but the first couple I did I just smoothed up the end of the crane with a stone. A regular knife sharpening stone will work with some oil.

You will need some shims that you can get through Brownells. There are two types: one for the crane and one for the cylinder. It sounds like you want cylinder shims. Put one in and see how the clearances work out. I generally order the .002" thickness and stack up what I need. The shim goes in the hole before everything goes back together.

Remember that the threads are left handed. Put empty brass on the holes to help spread the forces out on the star. Also be ready for the spring to fly the ejector across the room when you get loose fromthe last thread.

The first time you do this you will probably be afraid of tightening the ejector rod too much. This will result in it's unscrewing during your next match locking up your gun. Just be ready if you can't get your gun back open about half way through a stage.

But you'll figure it out.

Edited June 30, 2006 by Waltermitty

[Keith]

This sounds much more involved than working on the ol' Glocks that I'm used to.

But......I'm game. Besides, Zips confident we can do it with the right tools...... the most important of which will be a twelve pack.

Edited June 30, 2006 by Keith

[bountyhunter]

Not sure if it was covered but this is important:

On old guns that wear into end shake, the end of the crane tube cuts a groove into the inside face of the cylinder. That face has to be smoothed before fitting washers. The washers have the same outside diameter as the crame tube, but extend farther in (ID is smaller).

If you don't smooth the inside "ridge" on the inner cylinder surface cut by wear, it will bind up the washer.

Hope this makes sense to you.

[zip308]

...... the most important of which will be a twelve pack.

Its amazing how confident I can become with a couple of beers in me. Too bad I cant have a few before I shoot.

[bountyhunter]

Put empty brass on the holes to help spread the forces out on the star.

9mm brass will hold a .38/.357 star MUCH tighter than .38/.357 brass. The 9mm brass is a "tight fit" and doesn't go all the way in, so it holds the star from any movement when torqueing on the rod.

[10mmdave]

Put empty brass on the holes to help spread the forces out on the star.

9mm brass will hold a .38/.357 star MUCH tighter than .38/.357 brass. The 9mm brass is a "tight fit" and doesn't go all the way in, so it holds the star from any movement when torqueing on the rod.

Excellent idea BH

One of those "now why didn't I think of that" deals !

[Waltermitty]

...... the most important of which will be a twelve pack.

Its amazing how confident I can become with a couple of beers in me. Too bad I cant have a few before I shoot.

We've been tossing around the idea of a Tequila Shooters Sectional (TSS). Each stage description would be something like: "...at start signal, down Tequila and engage targets as they become visible...". There's several rule details to work out, like how many reshoots to limit each shooter to during the match, designated RO's, etc.

The prize structure could include most stages completed before DQ (or passing out), passing the sobriety stage (in lieu of chrono), with Grand Prize going to whomever can walk to the front and pick it up at the end of the match.

There are other details of course, like what range would host it and if it should be done at night, but there's bound to be some video opportunities in there somewhere, listing on Weird News, Darwin Awards, etc...

[Round_Gun_Shooter]

There are other details of course, like what range would host it and if it should be done at night, but there's bound to be some video opportunities in there somewhere, listing on Weird News, Darwin Awards, etc...

Just do it with Paint ball. See if you can get someone to load them as Jello Shots

Regards,

[D.carden]

I get tired just read'n this thread...........Oh, how many times have we all performed this operation... ........ and on the same gun too......

Cant wait for the next one....