Cylinder hangs up during rotation every 6th chamber

[Metal god]

Our range is opening up next week and I'm going !!!!!!! However the last time I shot my GP-100 I was doing some single action shooting and I noticed every 6th pull back of the hammer there was more resistance then the previous 5 .

I obviously stopped shooting and continued trying to figure out why . It was very clear it was doing this and very repeatable . Every 6th pull back of the hammer it was harder to pull back . This was loaded or unloaded it did not matter . Not a lot harder but noticeable and more resistance on the second half of the pull then the first half . At first I thought I bulged a cylinder but they all "seem" the same . I can't see anything that would indicate a physical problem . I wiped it down but have not cleaned it . FWIW after pulling the hammer back about 30 or 40 times it stopped doing it and now it seems fine but I have not shot it since and I want to next week .

I'm still concerned though because of the consistency of the issue . Am I wrong in thinking everything in the gun works and acts the same on every trigger pull back and fire except the cylinder ?? Meaning the cylinder advances the chambers so it's different every time but everything else actuates the same on every hammer and trigger pull ?? It just seems odd it would happen on every 6th cylinder , you'd think if it was something other then the cylinder it would happen more randomly .

I should also add that I switched out the trigger and hammer springs and shimmed the hammer . This was done hundreds of rounds ago ( more then 500 less then 1000 ) till that point everything was working great .

Any ideas ?

 

[JohnKSa]

Maybe some crud under the extractor that was causing it to bind on one side? I really don't know what would cause something like that and then go away.

 

[Hal]

I wiped it down but have not cleaned it

Get back to us with an update after giving it a thorough cleaning.

A good "cleaning" does wonders for things like guns, your attraction to the opposite (or same if you go that way) sex, your teeth, the insides of your car engine,,,,,etc,etc..

I should also add that I switched out the trigger and hammer springs and shimmed the hammer

After a good cleaning - that's exactly the place to begin troubleshooting the problem.
I spent over 25 years in the technical world of electronics and computers.

The most fundamental rule of troubleshooting is - go back to the last known good state.

Unless someone else can come up with something better, I'd suggest starting there. Replace the gun to its original shipped condition and see if you can replicate the problem.

You'll have to do that anyhow if you send it back to Ruger.

 

[Metal god]

Cleaning it before I go was/is kind of a given . I feel I may have worded what upgrades I did and when poorly. I intalled the springs and shims right away . Meaning I took the gun out brand new shot it as sent from the factory with factory ammo . That was about 150rds . I then changed the springs , shimmed the hammer and replaced the sights . I now have well over 500rds with the new configuration. These were Wilson combat parts , they should be gtg . I think just giving it a good cleaning and seeing if that fixes the problem is what I’ll do first . I was shooting slow burning powder that does not ignite well . I very well could have got some unburned powder stuck somewhere and not noticed it and just worked it loose .

I had not done a full disassembly cleaning in at least 200 rounds of dirty powder shooting which I had not given much thought to til recently . I’ll try that before returning to factory condition.

 

[Siggy-06]

If you have a feeler gauge, measure each cylinder at the forcing cone to see if there’s any variation.

 

[Don P]

^^^^^^^ What he said and I'll add this question, is it the same chamber every time?

 

[Metal god]

^^^^^^^ What he said and I'll add this question, is it the same chamber every time?

Yes same chamber every time .

I do have feeler gauges , You're saying measure the cylinder gap correct . I should clean first correct or do i want to measure dirty and clean . I have ajustable hole gauges but they’re little harder to work or I should say a little less consistent than pinhole gauges because I have to adjust to fit then measure which puts a lot of responsibility in the Person measuring

EDIT

I just tested the gun dirty and with the .007 gauge . One chamber hangs up quite a bit more than the rest and the two on each side hang up a little bit and the other three the gauge is rubbing but the cylinder is moving freely/Consistently . This is me pulling the trigger back and then releasing the hammer pulling the trigger back again releasing the hammer etc. etc. through the full rotation . When I come up to those three chambers that hang up the first one gets a little tighter the second one is noticeably tighter than it loosens up again for the third and then frees up for the next three .

Next is to clean and see if I get the same result . Just need a way to mark the cylinders/chamber’s in a way that won’t rub off while I’m cleaning

 

[Metal god]

OK with it clean . It still does it but not as bad . My feeler gauges say there is a .0015 to .002 difference from the one that hangs up and the chamber directly opposite of it in the cylinder . The one that hung up can take the .008 gauge but not the .009 gauge and the chamber on the opposite side of the cylinder can take the .009 and the .010 but the .010 is VERY tight .

So now what ? Is that not to unusual and it was just carbon and fouling built up binding the cylinder or is something very wrong ? Fingers crossed

FWIW doing this test gave a similar feel as it did when it was hanging up the first time noticed it . Not exact but similar .

 

[RKG]

I suggest you set up a dial indicator to measure cylinder pin run-out, looking for either a bent cylinder pin or a bent crane.

 

[Metal god]

I suggest you set up a dial indicator to measure cylinder pin run-out, looking for either a bent cylinder pin or a bent crane.

I don't know what those are specifically but have an idea . Either way would either of those cause only one chamber/area of the cylinder to be closer to the forcing cone . Just looking at the firearm it seems if anything was bent it would be bent in a fixed position and not cause a wobble . All chambers would be closer or further from the cone .

 

[Carmady]

delete

 

[Metal god]

I have one of these and one of those what do I need to measure and how do I go about it ?

 

[tangolima]

Metal,

First, does the revolver have any endshake? It is the back-and-forth play of the cylinder in the frame window.

Second, when you measure the cylinder gap, did you push the cylinder all the way forward?

Third, pull back in the trigger just enough so that the cylinder can be rotated by hand in the window. You will hear the sing; the ratcheting of the hand riding on the ratchet. Again with the cylinder pushed forward while rotating, do you feel the same resistance pattern?

I wish I am still doing gunsmithing. I was working at a small shop in Escondido, till my business partner passed away unexpectedly a few years ago. I could have fixed it for you. No charge for friends or combat veterans. Only parts & materials with no mark ups.

-TL

Sent from my SM-N960U using Tapatalk

 

[Metal god]

First, does the revolver have any endshake? It is the back-and-forth play of the cylinder in the frame window.

Yes but very little . If I had to guess , just enough for the tolerances needed . FWIW it's the same amount with the hammer down or cocked . There is the same amount of movement back to front no matter where the hammer is . Also there is significantly more movement in the cylinder when trying to spin/turn it with it locked in place , and that is not really all that much . I remember testing that before I left the store and it has the same amount of movement now as it did then , not much but more then it does back to front .

Third, pull back in the trigger just enough so that the cylinder can be rotated by hand in the window. You will hear the sing; the ratcheting of the hand riding on the ratchet. Again with the cylinder pushed forward while rotating, do you feel the same resistance pattern

No , there is no resistance at all doing that . Now that it's clean it's running smooth as butter . I mean unless I put a shim in there to bind it up .

Second, when you measure the cylinder gap, did you push the cylinder all the way forward?

No , but that's because I was creating pressure rearward as I lightly forced the feeler gauges in .

 

[tangolima]

Yes but very little . If I had to guess , just enough for the tolerances needed . FWIW it's the same amount with the hammer down or cocked . There is the same amount of movement back to front no matter where the hammer is . Also there is significantly more movement in the cylinder when trying to spin/turn it with it locked in place , and that is not really all that much . I remember testing that before I left the store and it has the same amount of movement now as it did then , not much but more then it does back to front .







No , there is no resistance at all doing that . Now that it's clean it's running smooth as butter . I mean unless I put a shim in there to bind it up .







No , but that's because I was creating pressure rearward as I lightly forced the feeler gauges in .

Hammer position usually doesn't affect endshake measurement. Try measuring the cylinder gap with the cylinder pushed forward and backward. The difference in the results is the endshake. Any amount of endshake is undesirable. But there is a upper limit over which action should be taken to correct.

Measure cylinder gap again with the cylinder pushed forward. It is what's going on when the cylinder advances. The hand pushed it forward. If you can't shove the thinnest feeler gauge in there when the cylinder is pushed forward, you may not have enough cylinder gap.

If you manually spin the cylinder with the trigger pull back while pushing the cylinder forward, and you don't feel the resistance, it is a good hint to the issue. It is most likely cause by the bolt or cylinder stop. Now try advancing cylinder normally single action. Observe the movement of the cylinder stop while you are doing it, especially the chamber in question. Possible the cylinder stop doesn't clear the recess in cylinder in time.

-TL

Sent from my SM-N960U using Tapatalk

 

[4V50 Gary]

Moved to Smithy.

Feeler gauge for clearance front and back.

It could be the crane is bent and thus it binds the cylinder.
If the crane is not bent, then it could be the ratchet. Can you mark the cylinder it binds on?

 

[Scorch]

If it is hanging up every 6th cycle of the action, it's the ratchet. Probably a burr or slight galling. Rugers operate like S&Ws, timing is hand bypass on the ratchet pad, so every 6th time you cycle the action it is at the same point on the ratchet. Mark which pad and examine it closely.

 

[Unclenick]

I would remove the grip panels and clamp the gun in a vice with padded jaws and set your yellow-face indicator up to measure the back end of the cylinder on the left side as it goes around. If, as suggested, the pin or crane are bent, you should see the back end of the cylinder surface move left just before the action feels hard to operate. This would be due to more interference by the hand/pawl with the ratchet teeth of the ejector star as it goes past that point. We're looking to see if the interference between the hand and the star is greater when the difficult chamber is lining up with the barrel. If the cylinder rotation is even, then look for crud to be pushing the star itself to the side in the cylinder. Check, too, for any burrs that would interfere with the star fit into its recess in the cylinder, as that may push it a little to one side as well. This is sensitive. Just a thousandth of forced interference can make a difference in the interference feel.

 

[Scorch]

If the crane were bent, it would not cause a cyclic hangup because the crane does not rotate with the cylinder. Besides, Ruger cranes are super beefy, I can't imagine one getting bent without some serious visible damage. The center pin on Rugers is about 1/4" long and does not fit tightly in the ejector.

 

[Metal god]

Hammer position usually doesn't affect endshake measurement. Try measuring the cylinder gap with the cylinder pushed forward and backward. The difference in the results is the endshake. Any amount of endshake is undesirable. But there is a upper limit over which action should be taken to correct.

OK I did this in two areas , one on chamber that hung up and the other side of cylinder . FWIW I found that when pushing forward by hand I could push gauges in that otherwise would not because the cylinder would move back a little . So I placed a flathead screwdriver in the rear gap . No torque or anything , just slid it in there to have a more ridged stop .

Hanging up side = pushed forward unknown because I don't have feeler gauges below .006 , the .006 would not slide in . Pulled back .009 would not go bot .008 felt kind of loose . The .008 was rubbing but not as much as I thought it might since the .009 did not go .

Non-binding side = Pushed forward .006 slid in but pretty tight . Pulled back .010 slid in but once again pretty tight

I would remove the grip panels and clamp the gun in a vice with padded jaws and set your yellow-face indicator up to measure the back end of the cylinder on the left side as it goes around.

The indicator I have measures in millimeters didn't realize that when I bought it . Here's what I got

As I rotated the cylinder the needle bounced around in the .03mm area . Mostly .02mm but would drop into the .01mm and rise up into the .03mm areas . How ever one area of the cylinder ( opposite the chamber that hangs up ) the dial raised up to .07mm . If my google-foo is correct , that translates to most of the cylinder moved about .001" then wobbled .0025" .

I also measured it with the cylinder open and it was almost perfectly straight , it stayed inside .02mm

I have not inspected the star or other parts fully yet . That's next and I'll update with some high res photos . Need to pull out the good camera for that , those above are with my phone .