Cylinder binding problem .002 gap too tight?


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elano
August 14, 2011, 10:52 PM
I have a ruger security six that binds the cylinder up when it gets hot from firing. When it's cool it shows no symptoms. I measured the gap with a feeler gauge and with the cylinder being pushed forward I can BARELY squeeze a .002 in there. With it pulled back I can fit a .004 but not a .005. There are circular scrape marks on the cylindar face in the buildup between a couple bores. This lead me (haha) to believe that the cylindar to barrel gap is the problem after everything gets warm.

I read that a knife sharpening stone or fine file can be used to carefully take a thousandth or two off the barrel end. Is this ok to do?

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918v
August 14, 2011, 11:16 PM
No.

You might have a bent ejector rod causing runout between the cylinder and the forcing cone.

Is the gap consistent with all chambers?

Jim K
August 14, 2011, 11:24 PM
Yes, if you plan to shoot more than a few rounds at a time. The optimum b-c gap is .006-.007. Some folks seem to think that the b-c gap should be close to zero, concentrating on loss of pressure and forgetting about cylinder expansion from heat.

Jim

Flint Ridge
August 14, 2011, 11:26 PM
as 918v stated, is the binding on all cylinders? Or does it get worse, worse, then better and better, then back to worse? I've had that issue myself.

Jim K
August 14, 2011, 11:36 PM
My response was based on the gap being consistent. If it is, a gunsmith with the right tool can take a smidgen (1 smidgen = .005" or .13mm) off the end of the barrel. Don't try it with a file.

If the gap does vary from chamber to chamber, there is a somewhat deeper problem and I would consider returning the gun to Ruger.

Jim

murf
August 14, 2011, 11:36 PM
check the gap at two or three different spots on the cylinder. your base pin hole on the cylinder may be off line with the bores. if so, a .002 gap will tie up the cylinder with a minimal amount of crud on the face of the cylinder.

murf

elano
August 15, 2011, 12:55 AM
Well if it was something mechanically bent like the star rod or crane, it should do it all the time, not only when hot am I right. But to answer your question, it seemed to do it every 6th trigger pull however examination of the cylinder face showed contact with the forcing cone in 2 places.gap looks to be consistent and true all the way around.

I'm shooting lead reloads and it seems to be leaving a thin lead residue on the cylinder face around the bores. I might buy some fmj and see if it does it with that now that I scrubbed it clean with a bronze brush.

F-111 John
August 15, 2011, 01:14 AM
You need to measure the gap six times. If the face of the cylinder isn't perfectly square (and they rarely are) you will find one chamber with the highest gap and the opposite chamber has the lowest gap.

If the chamber with the highest gap is .002, and the chamber with the lowest gap is <.002, you have a problem.

On my Dan Wesson 715, you can set the gap because of the interchangable barrels, and the gun comes with an .006 feeler gauge to set the gap. The gap goes from a bit loose to very snug on the .006 feeler gauge when measuring all six chambers. Over on the Dan Wesson forum some like to set their gaps at .004 claiming better accuracy, but all agree that anything less than .004 is asking for your type of trouble.

My S&W Model 19 has an average gap of .008 with a similar loose to very snug between all six chambers.

Not only will a .002 gap cause problems when the cylinder heats up, but the smallest amount of fouling on the face of the cylinder can cause cylinder-forcing cone drag.

918v
August 15, 2011, 01:38 AM
Well if it was something mechanically bent like the star rod or crane, it should do it all the time, not only when hot am I right.

Nope. If it's bent, it's bent. It may not make a difference when cold. Spin the cylider and look at the ejector rod. Is there a slightest hint of wobble?

This sort of thing is caused by people flicking the cylinder shut with their wrist.

madcratebuilder
August 15, 2011, 07:20 AM
If you have .000 runout on the cylinder then .002 barrel gap should not cause binding until you get the gun so hot you can't handle it. The factory spec for the Dan Wesson .357 Supermag is .002 barrel gap. That's what I run on mine and I don't have a binding issue unless I shoot until it's filthy dirty and hot as heck. Then I well start to feel some drag.

hardluk1
August 15, 2011, 09:36 AM
Contact rugers CS . They will more than likely have it shipped in to correct your issue. I keep my DW's also at 2th but they are hunting revolvers not for shooting up ammo like in there early life. You should have that gap a bit larger, about 6 th's 4th's if very square fit.. Ask then to smooth up your trigger too while they have it.

Magnumite
August 15, 2011, 06:03 PM
Is the ejector rod loose and coming unscrewed?

Remllez
August 15, 2011, 07:59 PM
Hardluck is right Ruger should take care of you...two thousands is too tight to be practical.
Have you had the gun awhile and this is a new problem?

OldCavSoldier
August 15, 2011, 08:28 PM
An old tool and die maker years ago told me that the optimum gap is .003 enough to take up any expansion but close enough to accept run-out of course this was back in the day when most revolvers did go thru *some* amount of hand-checking....and when quality was not just a word thrown around

Yarddog
August 15, 2011, 08:36 PM
The Gun was made before 1987, What's the pre fix #'s ?
Y/D

MachIVshooter
August 15, 2011, 09:44 PM
Check the forcing cone very carefully. the -Six series had the same cracked forcing cone problem as S&W K-frames, and that'll bind it up. Happened on mine.

elano
August 15, 2011, 10:11 PM
Serial is 155-xxxxx

Forcing cone is not cracked, ejector is not loose. I bought it a few months ago. When I spin the cylinder, the ejector rod looks pretty straight to me.

BCRider
August 16, 2011, 01:03 AM
When you're talking about .002 or so for a variation of course it'll "look straight". The human eyeball is only good for the sort of coarse things which would mean instand disaster in something such as a cylinder runout. You want to repeat your shim testing with a clean front face on your cylinder and to check all the chambers for gap.

Also since you were able to "open up" the cylinder gap to .004 with the cylinder pulled back then .004 is your gap, not .002. Pressure during the cylinder indexing will push the cylinder back as needed to work. So the proper gap in your case is .004 to .004+.

Magnumite
August 16, 2011, 02:55 AM
One more check...is there powder or debris between the extractor head and cylinder at the rear of the cylinder? That would force the cylinder forward.

Got_Lead?
August 16, 2011, 03:42 AM
If you remove metal off the back of the barrel, do so .001" at a time, and test fire. A well fitted BC gap is a precious thing.

I have a Taurus model 85 that had the same issues, .002 gap and it hung up as the face of the cylinder picked up a little fouling. I polished the face of the cylinder and squared up the back of the barrel. Function is 100% now.

If you do need to remove .001" or so off the back of the barrel, I would recommend making a jig out of wood to keep the file flat across the barrel, otherwise you will likely round it.

Oh, and BTW, when you cock the revolver, the hand pushes the cylinder forward, so the rearward BC measurement is really moot. And when the gun fires, in most cases, the case slips fully rearward against the recoil lug, locking the cylinder forward as it expands and seals. Endshake can vary between .001" to .005" between guns. Your Ruger is pretty tight at .002 endshake (difference between forward and rearward BC)

I have 2 security sixes, one measures .002/.006, and the other is .004/.005. I've had the former for decades and the endshake has not changed in thousands and thousands of rounds.

You might give Ruger a call before removing metal. Remember, metal is easy to remove, but slightly more difficult to put back.

Good luck.

oldfool
August 16, 2011, 09:01 AM
Opinions vary on just how tight is too tight for b/c gap, always have, always will
but, yeah, 0.002 will bind cylinder when the cylinder face accumulates powder residue

unless you are a qualified professional gunsmith, do yourself a big favor, leave the stones and files alone, and sent it to a pro or the factory

"There are circular scrape marks on the cylinder face in the buildup between a couple bores." Cannot say that something else like an ejector rod etc. could not be cause, but the tight gap is the primary suspect, yes, that is the very typical observed symptom.

(shoot slower, or clean face more often, or send it to a pro)

elano
August 16, 2011, 07:50 PM
Thank you gotlead and others who replied!

I have scrubbed the forcing cone and cylinder face clean with a bronze brush and will shoot some fmj 357 rounds through it this weekend. I figure if I can make it 100 rounds with no problem Ill leave it alone. Otberwise it's gettig fixed one way or another.

Anyone know how much a smith might charge to take it down a thousandth or two? If it's goin to cost $50 I might just do it myself. I know a little bit goes a long way when it comes to clearancing tight fitting parts.

gamestalker
August 16, 2011, 09:59 PM
That much movement seems kind of sloppy to me? One of my S&W 66's has had a long steady diet of H110/296 loads through it, and it still won't move but maybe .001" if I really push hard on it. But more to your question. I personally think .002" is a little too tight for a magnum revolver, especially if it is flexing as much as your describing. Mine are all in the .004" -.006" range.

918v
August 16, 2011, 10:06 PM
Anyone know how much a smith might charge to take it down a thousandth or two? If it's goin to cost $50 I might just do it myself. I know a little bit goes a long way when it comes to clearancing tight fitting parts.

For $50 you might as well send it to Ruger and let them fix it correctly.

Jaymo
August 16, 2011, 10:09 PM
My first revolver was a 1990 -91 Charter Arms Bulldog .44 with the 2.5 inch bull barrel. Only one I've ever seen.
It had a cylinder gap of 0.0015" and it never did tie up. I shot the snot out of that revolver.
Maybe I was just lucky?
I seem to recall the feeler gauge that comes with Dan Wesson revolvers was/is 0.006".
I don't measure cylinder gap anymore, unless I have a problem with the gun tying up.

madcratebuilder
August 17, 2011, 11:07 AM
I seem to recall the feeler gauge that comes with Dan Wesson revolvers was/is 0.006".

It depends on what model. My 15-2's have a .006 gap gauge. My 740VS has a .002 gap gauge. I have run as tight as .001 on the 740 and did not have any drag until the third set of six rounds. I run my 15-2's at .004 and have never had any drag.

To run these tight gaps the cylinder has to be true. A runout of .001-.002 well cause you problems when you tighten it up.

oldfool
August 18, 2011, 08:34 AM
depends on what you do with your gun, of course, need not be an either-or

I have a pair of S&W k-17s, one TH/TT with 0.002 gap, the other with 0.0045-0.005 gap
Which one I pack in the range bag (sometimes both) depends on my intent
The tight one is good for 5 to 6 dozen rounds before binding; then must rub down the cylinder face with CLP patch, good to go again; the other is good for a full brick or more "as is"

both "less filling, taste great".. shoot straight, run smooth, slow or fast

JK and madcrate both know 'precisely' what they are doing, and why
both comments very much on target, know your gun and your target

doesn't hurt to own more than one gun, just pay attention to what you carry on your hip, and what you carry only to the range

Cemo
August 18, 2011, 11:26 AM
I don't understand why a binding issue is just now popping up on a Security Six unless it is lead build up, which a good cleaning should cure. I've had binding issues with two Rugers, a GP100 and a .22 Single Six Convertible. In both cases as the gun heated up and the cartridge case heads would bind as you tried to rotate the cylinder. I found there was a lack of clearance on the rear of the frame window (Recoil Shield) near the bottom. A little metal removal and polishing on the bottom of the recoil shield cured the binding issue.

elano
August 22, 2011, 11:42 PM
Alright yall here's a happy ending!

I scrubbed the forcing cone and cylinder face squeeky clean. Made it 100 round without binding up!

Thanks to all who replied.

fastbolt
August 23, 2011, 06:43 PM
As others have already suggested, call Ruger and let them have a chance to examine it and correct anything they feel requires correction.

Just because you may have observed an apparent symptom with your revolver, that doesn't mean you've correctly identified the underlying problem.

Barrel/cylinder gap tolerance may vary among different designs and models, depending on the manufacturer. In the S&W revolver armorer class they tell armorers that the recommended B/C gap ought to be within .004 - .010", and the Go/No-Go feeler gauges provided to check it are those dimensions. The gap is checked by inserting the narrow feeler gauge from the frame side (left side, as the muzzle is pointing away from you), at the top of the gap.

I've had a brand new S&W come with a rather tight .004 gap, with minimal (but necessary) endshake, and exhibit some signs of the cylinder face hitting against the edge of the barrel at times. Checking several of my other S&W revolvers of various vintage, they seem to run around .005 - .008" ... and they all shoot very well. Doesn't it just figure that the newest production one would have a tight B/C gap? :neener:

I've not felt like checking my Ruger Service-Six or SP101 using feeler gauges, since they shoot so well (and I had one of them "duty tuned" by a very reputable gunsmithing company back when I was carrying it a lot off-duty). I had a problem with the SP101 cylinder "seizing" as the gun heated up, and after consulting with a LE revolver armorer (before I became a revolver armorer), it turned out the actual underlying condition had nothing to do with the B/C gap, but was a burred part encountering another part when they heated up. Once I relieved that burred spot ... and dressed the corresponding burr caused on the other part ... the "seizing problem" occurring when a few cylinder loads of hot Magnum ammo was fired was resolved.

I'd let the company have first chance at examining it. If they decline to check it, then I'd look around for a reputable gunsmith familiar with Ruger revolvers to check it.

Just my thoughts.

hardluk1
August 24, 2011, 02:29 PM
hay way to go back and running fine.

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