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Discussion Starter · #1 ·
I need to know whether this is something to be concerned about or not: At a certain point during the arc the cylider makes when heading toward lock-up in the frame, the front face of the cylinder drags slightly across the breech end of the barrel. It's not enough to cause difficulty closing, but it is noticeable. Just to be sure it was happening, I Sharpied the face of the barrel, and sure enough the black got rubbed. There is no interference when the cylinder is turned during operation of the gun. B/C gap seems to be about .005", about the same as another SP I have. I did notice that the B/C gap is larger at the bottom than top.

Also by comparison, I could not get the other SP to have this barrel/cylinder contact.

Please advise and thanks for you input.
 

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Clayton, When the cylinder touches the barrel, it's an indication of excessive endshake, a cylinder with excessive runout, or a barrel that was not trimmed properly at the factory .... possibly a combination of these. A larger gap at the bottom also indicates the barrel was not trimmed properly at the factory. A little more information would be helpful ... What caliber? Is the gun new and if not, how many rounds have been fired? Have you checked endshake and if so, what were the results?

With a .005" B/C gap and the barrel touching the cylinder, it appears you have at least .005" of endshake ... unless the cylinder has that much runout. Please advise.
 

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If you have been shooting lead it is possible that there is a build up on the forcing cone and/or cylinder face which can cause drag. Ive noticed that sometimes leading can be vary uneven and will exaggerate slight variations in the cylinder face or forcing cone that are otherwise not noticed, i.e. you have lead build up on the forcing cone and it drags on only one or two cylinders or it appears to have an uneven b/c gap. I'd start with a good cleaning and see where it takes you.

If it is only making contact with the forcing cone during opening and closing of the cylinder and doesn't contact in full lock up you might just be pulling the crane out a little while it is closing, if I remember correctly the crane moves in and out slightly while fully open as if it is being held in by a spring, the difference between the two is you might have one with a little looser tolerances than the other.

The most important aspect is to look for contact while the cylinder is locked into the frame. It is a good idea to check the endshake with a set of feeler gauges at full lock up as Iowegian suggested, this will tell you if there is an important issue at hand.
 

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Discussion Starter · #4 ·
This is a .357 SP101 with a 4.2" barrel. I bought it used but in excellent condition with 25 rounds through it. I have put about 400 low power cast .38SWC through it.

It has already been back to Ruger once because of a bad fit between the ratchet and pawl which caused poor trigger pull and occassionaly binding. That problem is fixed but now I have this. I did not detect if this issue existed before the trip to the factory. I'm starting to feel like I got a lemon.

I'm not rough with guns. No drops or anything traumatic. I was dry firing a little too fast, maybe between 100-200 times, until I read the post containing your advice about that, so the cylinder notches received some very minor peening, but nothing I'm too worried about. Don't think that would affect this anyway.

My set of feeler gauges only go down to .005, but I can tell you this about endshake: When I push the cylinder forward, I can almost get the .005 gauge under the bottom of the gap. When I push the cylinder back, I can get a .006 gauge only in the bottom of the B/C gap. Seems like not alot of endshake.

This gun is clean, all traces of leading and fouling have been removed.

Thanks
 

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Clayton, Sad to say ...it looks like your SP-101 needs to take another trip to the factory. Looks like it needs to have the barrel trimmed square and possibly a new cylinder fitted.
 

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Discussion Starter · #6 ·
Just got off the phone with Ruger customer service. I described the problem to the man and he got out an SP right there and told me that his dragged the cylinder face across the forcing cone as well and that it was probably normal. The fact that his does it too wasn't too comforting or convincing. We talked about it a bit more and I told him about the uneven cylinder gap and he told me that if I wanted to send the gun in I could. I took him up on it.
 

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Iowegan is quite right on his explanation of things. The only other thing I can think of is a bent or out of spec crane alignment. I usually saw this more frequently with Smith and Wessons, but it can happen to any revolver. Hearing that the top contacts closer than the bottom of the forcing cone it could have come from a bent crane, however it would only be slightly noticeable. If the crane gets bent too much, the cylinder wouldn't lock up. Do this. You already know that the cylinder is out of sync at the end. Now look at its rotation from the side ie. the bottom of the cylinder as it passed the bottom of the frame. If that is also off, you've got a bent crane (among other possible things). Smithy.
 

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Cylinder

Clayton, When the cylinder touches the barrel, it's an indication of excessive endshake, a cylinder with excessive runout, or a barrel that was not trimmed properly at the factory .... possibly a combination of these. A larger gap at the bottom also indicates the barrel was not trimmed properly at the factory. A little more information would be helpful ... What caliber? Is the gun new and if not, how many rounds have been fired? Have you checked endshake and if so, what were the results?

With a .005" B/C gap and the barrel touching the cylinder, it appears you have at least .005" of endshake ... unless the cylinder has that much runout. Please advise.
Does using shims hurt the crane to cylinder mating in the long run:confused::D
 

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3482jl, "shims" ... I guess you mean endshake bearings, which are nothing more than very thin washers. No, they won't hurt the crane to cylinder mating surface providing they are installed properly ... in fact they improve it. You have to remove the "gouge" in the cylinder center hole mating surface before you can install endshake bearings. Otherwise they will never mate properly.

Smithy, A bent crane will not make the cylinder change gap distance as it is rotated. Only a cylinder with runout will do this.
 

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Smithy, A bent crane will not make the cylinder change gap distance as it is rotated. Only a cylinder with runout will do this.
Not Ruger's mind you, but I have seen Smiths do this very thing. I had a very expensive Brownells tool to straighten cranes and fixed a couple of coworker's guns that had that very same problem. However it was on all occasions that the meeting of the barrel to cylinder was reverse of the poster's problem. In other words the bottom of the forcing cone was in closer contact than the upper. The cause of this condition I still don't understand, unless the gun was dropped with the cylinder swung out all the way and landing on the cylinder. That would bend the yoke down and in towards the frame resulting in the conditions I found. Smithy.
 

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There is no interference when the cylinder is turned during operation of the gun.
That part has me confused. If the marker shows that the cylinder is making contact with the barrel, then you have interference.
 

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I bought it used but in excellent condition with 25 rounds through it.
Really? Was it the previous owner who told you that it was in excellent condition?

It has already been back to Ruger once because of a bad fit between the ratchet and pawl which caused poor trigger pull and occassionaly binding.
indicating that nobody at customer service has a clue. The binding was most likely caused by the b/c gap, which obviously was not even checked.

Just got off the phone with Ruger customer service. I described the problem to the man and he got out an SP right there and told me that his dragged the cylinder face across the forcing cone as well and that it was probably normal.
...if this is a true tale, then there is no hope. That guy was probably selling shoes last week. Of course it is NOT normal. If your cylinder drags, it will bind up completely after a few rounds are fired. Are you happy that it might go 3 rounds before becoming useless?

If you decide to keep this item, you will have to measure everything (get a good set of feeler gauges first), write it down, take some photos and post the info in this thread. Then we might be able to see what the main problem(s) are, and whether it makes sense to continue. The value of the individual parts like trigger group, hammer and cylinder will probably repay your investment. Your choice. My instinct on this situation is that a backyard gunsmith had his way with it. Let's hope it was not the factory "normal". My 2 cents worth.

Eor
 

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Discussion Starter · #13 ·
Perhaps I was not clear in my original post. The front face of the cylinder is making contact with the rear face of the barrel as I close the cylinder into window, as one would do to ready the gun for firing after loading. Once the cylinder is in place there is clearance between the barrel, but it is slightly larger at the bottom of the gap. It appears that the plane of the cylinder face is not perpendicular enough to the bore. Something is a little off.

That does not seem to be as big an issue as if it were touching while the cylinder were turning during operation, but it still does not seem normal. I can not get any other SP to do the same.

I'm sending it back to Ruger on their dime. Seem like a reasonable thing to do or am I being too particular?
 

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Speaking as a Ruger and S&W Armorer, cylinder fit issues require personal inspection by a trained, experienced hand. I have dealt with them for thirty years, and they are not something that can be referred to a committee.

Because of the weakness inherent in the finite tangent between yoke button of a Smith vs. the heavy cradle under the Ruger crane (same part, different names), Smiths are notorious for endshake and distortion issues, but Rugers are not. When a Ruger is having cramping issues, it's a factory issue. There are a lot of old wheelgun Ruger Armorers around like me. Check with your local PD and see if anyone does this in his spare time and maybe you'll have it corrected in ten minutes without waiting for the turnaround time. Might cost you a new washer and a beer. :)

My educated guess is that something is wedged between crane and cylinder, such as a piece of copper jacket or lead, causing it to cramp. I had a spring get under one side of the washer once, and it caused that issue. Dismantling the crane assembly unless you are trained is not recommended, as re-tightening incorrectly can distort or scar things. Lockup is only critical to rotation; not to endshake. Never trim your barrel. That will only make for uneven clearance if the cylinder is cramping, and your issue is still unresolved, even if it's not hitting, and you'll have an out-of-spec gap and uneven pressures to cause accuracy issues.
 

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Discussion Starter · #17 ·
update with picture

OK, got the revolver back from the factory. Only description of work done is "repaired barrel gap". The gap is now uniform. The cylinder face does still make contact with the barrel when I close it into the frame, but the contact is much lighter and happens evenly rather than localized on the surface near the same two bores.

The crane looks like someone took a tubing cutter and scored it. Also has some small flat spots like someone did some hand work with a file. Copare it to the other crane from another SP. IT looks much smoother and has a constant diameter. The smooth crane actually fits tighter in it's own cylinder and in the cylinder that went to factor with less "slop" or what you could call runout. I can't swear the crane was like this before I sent it in but I think I would have noticed. Doesn't look too pretty, but I guess if the gun works and it's to factory spec, it's good to go.

 

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All that work was done by hand, by a skilled fitter, and the rings are the result of stretching the crane with a method that does, in fact use a sort of tubing cutter. Most likely, this was after a truing operation which required a couple of thousandths of metal to be removed at the end, thereby shortening it. If it were a S&W guy, by their method, he would have stretched it over a mandrel with a ball-peen hammer. Both methods work, but I think Ruger's is better because it doesn't raise up burrs that require even more filing.
 

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Clayton, I don't know, but the pics look bad although it's "fixed."

My 3" GP had the same thing that you initially described-cylinder strikes the forcing when closing the cylinder. My cylinder was also rubbing the forcing cone through its entire rotation. I installed a couple of Power Custom end-shake bearings and all was good.
 
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