Cylinder quirk: what does it mean?

[P. Plainsman]

After 700 rounds and a month or so of dry-firing, my new 4" Ruger GP100's action is getting noticeably slicker. I like it.

Or rather, about 80% of the time the action feels slicker. The gun has one foible, and that's what I want to ask about. From time to time, I pick it up for dry-fire practice and the trigger pull is tight, as if the cylinder were binding a little. It's not unmanageable, just heavy and uneven.

The usual form this foible takes is one heavy pull out of every six, which (to me) strongly suggests some sort of unevenness in the cylinder. But occasionally I'll pick up the gun and find a consistently heavier pull. Then an hour later I might try again, and find my gun back to its smooth-pulling self.

What's going on here? The effect is fairly minor, but noticeable. The gun otherwise appears fine. Shoots reliably and seems as accurate as my green skills will allow it to be. It doesn't rattle. The cylinder gap is tight, which I know to be a good thing -- you certainly couldn't fit a credit card in there. When the gun is in full lock up, the cylinder is solid, displaying negligible front-to-back play and minimal side-to-side.

I wet-clean the gun with Hoppes #9 (and a couple drops of oil) after most range sessions, and do a brief dry-clean otherwise. There's a bit of visible discoloration built up on the cylinder faces and the -- is it called the forcing cone? the breech? -- but it doesn't seem like much. I wipe down those surfaces thoroughly when I wet-clean the gun.

I will be taking this Ruger to a smith soon for a trigger job. I'd like to know how to describe this glitch to him in more concise language than I've used above. Also what to expect in the way of a fix.

Many thanks!

 

[Jim Watson]

Do you clean out from under the extractor star? Sounds just like what happens when you get a few (or one!) granules of unburnt powder under the star. Keep an old toothbrush in your kit. Leave that area a bit dry so the crud doesn't gum up in oil. Eject empties with muzzle up so most of the fouling falls out.

 

[Standing Wolf]

Always clean the face of the cylinder and barrel breech with Hoppe's No. 9 and a bronze-bristled brush to remove the crud, then more of the Hoppe's No. 9 and a soft Nylon-brustled brush to remove any coppre left by the first brush.

 

[mattz357]

If you want to get the "black eyes" or powder rings off of the face of your cylinder, pick up a yellow lead removal cloth (***NOTE*** do NOT do this if your gun is blue). A few wipes across the face of the cylinder and it will be good as new.

 

[P. Plainsman]

I'll take the liberty of bumping my own thread up, since the problem with my GP100 hasn't abated. Indeed, it's gotten worse. I now regularly get a very heavy, tight pull on two out of six chambers -- to the point where it is physically hard to thumb-cock the hammer on those chambers.

After my last range visit I vigorously cleaned the cylinder face, breech, extractor, crane, the exposed bit of the hand, etc., with a bronze brush and plenty of Hoppes No. 9. There are still very faint "black eyes" on the cylinder face, but it, and the other working surfaces, look good: visibly cleaner and shinier now than they've been for a while.

Yet the problem persists and deepens. The GP is my defense gun, so it's doubly frustrating.

(Right now, I almost think that in a crisis situation I would be more likely to reach for my Buck Mark .22 (!) -- piddling round, but the Browning shoots crisp and even, and aims like a laser.)

I figure it is probably time to ship my revolver to Ruger (the problem I've described takes the gun "out of spec," surely?) or to a smith. But I thought I'd pursue your collective wisdom one more time.

PS: Thanks to the earlier commenters. Much appreciated.

 

[P. Plainsman]

I'll take the liberty of bumping my own thread up, since the problem with my GP100 hasn't abated. Indeed, it's gotten worse. I now regularly get a very heavy, tight pull on two out of six chambers -- to the point where it is physically hard to thumb-cock the hammer on those chambers.

After my last range visit I vigorously cleaned the cylinder face, breech, extractor, crane, the exposed bit of the hand, etc., with a bronze brush and plenty of Hoppes No. 9. There are still very faint "black eyes" on the cylinder face, but it, and the other working surfaces, look good: visibly cleaner and shinier now than they've been for a while.

Yet the problem persists and deepens. The GP is my defense gun, so it's doubly frustrating.

(Right now, I almost think that in a crisis situation I would be more likely to reach for my Buck Mark .22 (!) -- piddling round, but the Browning shoots crisp and even, and aims like a laser.)

I figure it is probably time to ship my revolver to Ruger (the problem I've described takes the gun "out of spec," surely?) or to a smith. But I thought I would avail myself of your collective wisdom one more time.

PS: Thanks to the previous commenters. Much appreciated.

 

[Jim March]

Get out the manual for that puppy, or download it off of Ruger's website as a PDF. Either way, you're going to need it, because the next step is to SERIOUSLY strip that bad boy down to component parts. Leave the sights on...everything else should be completely apart. *Everything*. Yes, you can do this yourself on a Ruger.

THEN clean everything.

Then, as you're putting it all back together, LOOK at it. Play with each bit. Play with how each bit rubs against another.

You might find something odd, or you might not. Odds are you won't, and just the cleaning alone will be the fix you need.

If not, it's off to the gun vet for that thing...or Ruger.

 

[Derm95]

Can you dry fire an unloaded gun and with a bright light light see the gap between the cylinder and forcing cone/barrel. If the gap is too tight, it will bind more with more use of the gun.
Same thing was happening to my Taurus Titanium 627 .357 mag. Some polishing and deburring of the breech end of the barrel eliminated the problem (at the expense of having a less tight gap).
Wherever you might take it for a trigger job, the gunsmith should be able to diagnose the glitch you describe.

 

[Derm95]

If you do what Jim suggested, you can also see how to change Hammer and trigger springs for a lighter trigger pull.
Even if the gunsmith works on the trigger and puts in lighter springs, ask him for the originals back and the Wolf reduced power pack (with other weights) that he used to replace them.

 

[JohnKSa]

Does this happen when dryfiring (when the gun's not loaded)?

Does the cylinder rotate freely when it is swung out for loading? With the gun in the nose down position and the cylinder swung out, you should be able to spin the cylinder and it should turn very easily.

Has the cylinder on this gun ever been "flicked" closed like they do on TV and in the movies?

With the gun unloaded, hold the gun in your right hand pointed upward so you can look at the right side of the gun. Slowly pull the hammer back until the bolt (half circle of metal poking up through the frame that engages the little divots in the cylinder) falls out of engagement from the cylinder. Stop pulling the hammer back and hold it in this position. At this point the cylinder should spin with a clicking noise. If you pull the hammer back too far you'll have to let it down and start again. Does the cylinder spin freely or does it bind at some point in the rotation. If it binds, can you see if it's binding at the front or at the back.

 

[P. Plainsman]

Again, many thanks for your thoughts.

In response to your diagnostic questions:

Derm95:

Q. "Can you dry fire an unloaded gun and with a bright light light see the gap between the cylinder and forcing cone/barrel?"

A. I can. It's quite snug, but as I slowly pull the trigger six times, I can always see at least a hair's breadth of light between the cylinder face and the forcing cone. My first suspicion was that I have the very problem that Derm reports having had with his Taurus Titanium; upon close inspection, though, I'm less sure.

JohnKSa:

Q. "Does this happen when dryfiring (when the gun's not loaded)?"

A. Yes. If anything, I don't notice the irregular stiff pulls quite as much at the range, b/c I'm concentrating on my sights. It is still noticeable, however.

Q. "Does the cylinder rotate freely when it is swung out for loading? With the gun in the nose down position and the cylinder swung out, you should be able to spin the cylinder and it should turn very easily."

A. I would say "quite easily," but not "very easily." Turns evenly, but it's a bit squeaky. When I clean, I have tried to oil the relevant crevices in the cylinder, but I haven't ever broken down this revolver.

Q. Has the cylinder on this gun ever been "flicked" closed like they do on TV and in the movies?"

A. No. Never. Mom brought me up better than that.

Q. Slowly pull the hammer back until the bolt . . . falls out of engagement from the cylinder. Stop pulling the hammer back and hold it in this position. At this point the cylinder should spin with a clicking noise. If you pull the hammer back too far you'll have to let it down and start again. Does the cylinder spin freely or does it bind at some point in the rotation? If it binds, can you see if it's binding at the front or at the back?"

A. The cylinder spins freely, but not loosely, when I do this; about a 1/4 rotation per flick of the finger. The spin does gets a little tighter at one point in each rotation. It does not "bind," as such. I see nothing going on in the back of the cylinder to suggest that it's binding there. I would therefore tend to think it's in the front. Again, hard to tell for sure, since the cylinder gap on this particular revolver is pretty small in general.

 

[P. Plainsman]

Just to aggravate matters, I'll throw in that I just dry-fired the gun a couple dozen more times, and the baseline, fairly slick pull was back. Delightful.

Then I popped the empty cylinder, gently re-closed it, gave a couple dozen more pulls, and voila, the "drag" returned -- this time once per cycle.

 

[Jim March]

The BEST possible answer is that there's a bit o' gunk in the cylinder's "axle" somewhere.

Strip it down.

 

[tc300mag1]

Tear it down and clean the cylinder axle sure sounds like that is problem to me.

Not very hard to tear down that far.

 

[R.H. Lee]

Does it always happen on the same chamber? Is the axle completely straight?

 

[JohnKSa]

Concur.

The only other option is that the ejector rod (the one internal to the cylinder, not the extension that you push to eject empties) is bent. But that's very unlikely.

I'm kind of surprised that it's this gunky this fast though--what kind of ammo are you using?

You probably need to get the cylinder loose from the crane to really get it clean. That's a bit tricky, and a bit trickier (for humans) to get it all back together.

Remove the cylinder crane assembly per the instructions in the manual.

There's a small hole on the top of the crane. Using a very thin punch--has to be smaller than the hole diameter--push down on the plunger inside this hole. Holding the pressure, push out the pin on the crane from left to right. The pin looks like a button from the left side of the gun.

When you do this the cylinder's going to come loose from the crane, the forward cylinder lock is going to fall out, the external ejector rod is going to come loose and the forward cylinder lock plunger and its spring is also probably going to fall out.

The plunger and spring you depressed MIGHT fall out, but I've never seen that happen.

The ball bearings might also fall out, but they're staked in place and don't usually come out.

You might want to look carefully at all that stuff to see how it goes together before you start.

Clean dirty things. Don't bend the internal ejector rod (Ruger calls it a "Center Pin Rod")--you'll hate it if you do. Don't try to disassemble the cylinder unless you have the special tool. It doesn't come apart so easy.

Reassembly is the reverse-- --don't you hate how simple that sounds?

Ok, reassembly.

Put a TINY dab of grease on the back of the cylinder lock plunger spring. Poke it into its hole, the grease will hold it in place as long as you don't get wild.

Push the cylinder back onto the crane. Push the external ejector rod over the internal ejector rod. It has a top and a bottom and it won't work upside down--this is why you looked carefully before taking it apart.

Now with one hand holding that assembly, use your second hand to position the forward cylinder lock in its place, compressing the forward cylinder lock plunger and spring slightly so the hole in the cylinder lock lines up with the hole in the crane.

With your third hand, take your thin punch and fully depress the plunger that started this whole mess.

Using your fourth hand insert the pin and push it into place through the crane and the hole in the forward cylinder lock.

See, that wasn't so bad...

I find it quite easy, actually--although I do have trouble buying shirts with the proper number of sleeves...

 

[P. Plainsman]

OK, the emergent diagnosis is pretty clear. I'll dig up my set of little screwdrivers (and my pair of extra arms ) and take a look at the cylinder axle. Thanks, folks.


Since John asked, I'll also bore you all by running down the different ammo I've put through this GP:

- a few boxes of Sellier & Bellot .38 spl FMJ -- the practice ammo sold at my range

- a few boxes of Sellier & Bellot .357 Mag softpoints -- ditto

- a box of Winchester White Box .38 spl FMJ -- cheap practice ammo; rather dirty

- 80 rounds of Federal Hydra-Shok 129 gr .38 spl +P JHP -- my self-defense load. Burns clean, super accurate. The only ammo that visibly improves my groups. *Love* this stuff. Would shoot it all day if I were rich.

- about 40 rounds of Cor-Bon 125 gr .38 spl +P JHP -- I comparison-shopped this defensive round against the Hydra-Shoks. Not half-bad, but the Hydras won.

- one (1) box of Armscor 125 gr .357 Mag FMJ -- Yikes! Crazy hotrod boomer ammo. A gun store guy in the boonies foisted this on me in my newbieness. Made me some new friends at the range. Those in other lanes walked over to learn what was producing the arclight strikes.

- a couple boxes of Federal American Eagle .38 spl FMJ -- bought this in bulk for cheap practice ammo. Unfortunately, it is filthy.

 

[JohnKSa]

Holding the pressure, push out the pin on the crane from left to right. The pin looks like a button from the left side of the gun.

That should read: "...push out the pin on the crane from RIGHT TO LEFT."

It won't go out the other way--sorry about that!

None of that ammo sounds particularly grimy--I wonder if surprises await you during your disassembly????