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Discussion Starter #1
I have been having an issue with my revolver. The cylinder locks upon firing and I cannot get it to move again until I remove the cylinder and reinstall it. With the cylinder removed and the base pin installed, it works like it should. It also works correctly with the cylinder installed as long as it is not loaded. It will hang up occasionally with a loaded cylinder. The base pin seems to stay tight, but I do notice some play in the cylinder both laterally and longitudinally. How much play is allowable? I cannot identify the problem and need some ideas from folks who know much more about the SA design and problems that arise than I do.
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Cycleman,
Sounds like the problem shows up only when ammo is in the cylinder, right? Is this a new problem? New gun? Used gun, but new to you? Reloads or factory ammo? My initial thinking is that is sounds like a headspace problem. Possible causes - ratchet bearing surface too deep in frame, ratchet extension from cylinder not long enough, recoil plate not fully seated. Any chance the cylinder is from a different gun? The cylinder needs to be fitted to your frame. It's not a drop in swap (unless you're really lucky). I'm assuming it's 45LC ammo and cylinder, but maybe it's 45 ACP. If you load the cylinder when it's out of the gun, does the ammo seat properly into the cylinder? When all put together, clearance between the back of the cartridge and the inside of the frame should be on the order of 0.006". Got anything to check that for starters?
 

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Discussion Starter #4
Wundermech, thank you for your response and ideas. First of all, the problem has been intermittent up until now. I fired one round yesterday and it happened again. Reloads is all I shoot. I know they are not the problem. I follow published data and I chronograph to verify approximate pressure regardless of the load.
The pistol is an original 45 Colt/ Acp SS Convertible and it has not had a thousand rounds through it. The Colt cylinder is the known problem child. I know it's not a worn out part, but it could be a defective one or a fit issue. The ratchet cam bearing surface appears new and sharp and projects enough to engage the cylinder ratchet. There are no galled areas on the ratchet or the cam, and the spring tension is fairly light when compared with the locking spring tension. I say this because I don't know how much tension should be present on either part. I have no idea about how to inspect the recoil plate fit.
I checked the headspace with a fired case and a loaded case in each chamber, and found headspace on the fired case to be 0.004". The loaded case, which is a new unfired Starline case, measures 0.006-0.007". Are these measurements reasonable? Also, the round that I fired yesterday easily slipped out the cylinder once it was removed from the pistol. I did not have to use the ejector.
Upon closer inspection, I noticed a circular line on the cylinder directly centered on the locking notches with a spot centered between a pair of notches having a spot a little brighter than the rest. This is obvious drag on the cylinder by the locking cam. Is this a normal occurrence?

BigG, thank you for your comment too, and I may have to follow your suggestion if it's something I can't fix.
 

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Cycleman,
The measurements sound OK to me. The circular line and spot are from normal use. Maybe the quickest way to nail this down is to see if there's any space between the head and the frame the next time you have the cylinder stuck. You should be able to eyeball that. Other than that, any chance the spent primers are pushed out of the primer pocket a little and dragging or are they still below deck so to speak? When the cylinder does get stuck, you can no longer feel the normal end play in the cylinder, right?

Other stuff - Ruger specifically instructs not to use reloaded ammo in their manual. So, I'd expect their first suggestion would be to try some factory ammo before they say send it in and we'll take a look. Also, both cylinders are scribed/engraved with the correct number on the end to indicate they're matched to your frame, right? No dings or burrs on the case rims that would prevent them from seating nicely in the cylinder? The smallest defect in the rim might be screwing you up. Firing pin retracts fully - doesn't protrude with hammer down?
 

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Cycleman, Your headspace measurements tell me your loads are too light. What is supposed to happen is .... the primer generates enough pressure to thrust it back the same distance as headspace, .006~.007" in your gun. As powder begins to burn and generates chamber pressure, the case is forced back until it fully contacts the frame's recoil shield. This will push the primer back in the primer pocket where it is flush with the case head. In your measurements, you stated headspace with a fired case is just .004", which means your cartridges are not developing enough pressure to fully reseat the primers. The solution is quite simple .... there's nothing wrong with your gun, just increase your powder charge!
 

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Discussion Starter #7
Cycleman,
The measurements sound OK to me. The circular line and spot are from normal use. Maybe the quickest way to nail this down is to see if there's any space between the head and the frame the next time you have the cylinder stuck. You should be able to eyeball that. Other than that, any chance the spent primers are pushed out of the primer pocket a little and dragging or are they still below deck so to speak? When the cylinder does get stuck, you can no longer feel the normal end play in the cylinder, right?

Other stuff - Ruger specifically instructs not to use reloaded ammo in their manual. So, I'd expect their first suggestion would be to try some factory ammo before they say send it in and we'll take a look. Also, both cylinders are scribed/engraved with the correct number on the end to indicate they're matched to your frame, right? No dings or burrs on the case rims that would prevent them from seating nicely in the cylinder? The smallest defect in the rim might be screwing you up. Firing pin retracts fully - doesn't protrude with hammer down?
Wundermech, I have looked hard at the cylinder from every angle with the loading gate open and closed, and I hate to admit that I have not looked for the condition you described, but I will. I'll look for a gap the next time. And yes, when the cylinder sticks it doesn't have any play. I do pay attention to my primers too. I always inspect them before and after firing. Your comments have reminded me of a post where someone's firing pin was sticking and causing a lock up situation. Now I'm wondering if the firing pin could be stuck in the primer pocket after ignition and not retracting until I force it out when the pin is released. I certainly cannot rotate the cylinder pulling the hammer back. I have not noticed the firing pin protruding from the recoil shield with the hammer down.
I understand the manufactures position regarding handloading. They have no way of knowing who does what and how often. I will comply with their policy if I have to send it back if they insist that I do.

I did not know about the cylinder serial numbers. I will check that and make sure mine are paired. The cases are all in very good condition.

Thank you again for your interest in helping me figure this out.
 

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Discussion Starter #9
Okay, Iowegan and Wundermech and fired one round this afternoon and the cylinder is locked. The round was another SNS 250 grain coated cast bullet. My chronograph recorded 1290 fps. I took measurements and pictures and I still have not removed the cylinder just in case you fellows have more suggestions for me. The headspace is 0. I cannot get a feeler gauge between the barrel and fired case. The picture clearly shows the cylinder ratchet pressed against the recoil shield. I loaded three rounds each of them in consecutive chambers. I was able to get a 0.200 gauge between the unfired rounds and the recoil shield. I really don't know what this measurement should be and it may be relevant to the issue I'm having.
143564
 

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Cycleman, Let's start at the beginning. Headspace should be .008 ~ .012" with .010" being optimum. This is measured with an automotive type gap gauge by sliding the thickest blade possible between factory case head and the firing pin hole. Endshake should be no more than .005". If headspace or endshake is too generous, the case head can push back and expand, thus locking up the cylinder. That'e exactly what I'm seeing in the photos, however based on your chronograph data, it appears your chamber pressure is just too high!

If you are getting close to 1300 fps, that means you are definitely in the "Ruger Only" pressure range .... your ols HS-7 could be way over safe limits. The only powders I would use for this velocity would be 4227, H-110 or W-296. Anything faster burning will exceed pressure limits. This is just the opposite of what I said before because I thought you were loading too light.

Reloads is all I shoot. I know they are not the problem. I follow published data and I chronograph to verify approximate pressure regardless of the load.
My suggestion .... don't try to create a 454 Cas out of a 45 Colt. Get rid of that old HS-7 powder .... its not listed in any current reloading manual or even QuickLOAD. Tame those loads down to chamber pressures well under 30k psi and your problems will go away. Meantime, measure endshake and headspace with a factory cartridge and see what's going on. If either of these two specs are too generous, you should NOT shoot Ruger Only loads.
 

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Discussion Starter #11
Cycleman, Let's start at the beginning. Headspace should be .008 ~ .012" with .010" being optimum. This is measured with an automotive type gap gauge by sliding the thickest blade possible between factory case head and the firing pin hole. Endshake should be no more than .005". If headspace or endshake is too generous, the case head can push back and expand, thus locking up the cylinder. That'e exactly what I'm seeing in the photos, however based on your chronograph data, it appears your chamber pressure is just too high!

The headspace was less than 0.008 for each chamber. The brass was new Starline brass. I used a Starrett gauge for measurement.
I have not checked endshake, but I will do that next. As far as the case head expanding, I have not noticed any. The brass was easily removed from the cylinder the last time this happened. I have not removed the cylinder since I fired the gun today, but I'll check it very closely.

If you are getting close to 1300 fps, that means you are definitely in the "Ruger Only" pressure range .... your ols HS-7 could be way over safe limits. The only powders I would use for this velocity would be 4227, H-110 or W-296. Anything faster burning will exceed pressure limits. This is just the opposite of what I said before because I thought you were loading too light.

I agree, this is a Ruger Only load, but again, I am using original published data. This load turns out to be a maximum load in my gun. The maximum listed for the 250 grain bullet is 18 grains of HS7 generating 30K CUP. Comparing velocities, I was there, and I believe that I followed standard protocol by working up the load. I certainly would not increase it any. I do not plan to shoot all maximum loads in my pistols, but I have read many articles and looked at lots of data, and these guns should be able to function safely with the pressures generated unless the testing is flawed. Attached is the page from Hodgon's No. 26 manual.



My suggestion .... don't try to create a 454 Cas out of a 45 Colt. Get rid of that old HS-7 powder .... its not listed in any current reloading manual or even QuickLOAD. Tame those loads down to chamber pressures well under 30k psi and your problems will go away. Meantime, measure endshake and headspace with a factory cartridge and see what's going on. If either of these two specs are too generous, you should NOT shoot Ruger Only loads.
Thank you, Iowegan, for your insights helping me figure this out. You know far more about guns than I ever will. I'm going to check the endshake and go from there. I have learned a lot about my revolvers on this forum.
 

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Discussion Starter #12
I have now checked for cylinder endshake and I could not get a 0.015 gauge between the cylinder and barrel. I am not sure that the method I used to check it was correct. I wedged the back of cylinder with folded paper on each side. This kept tension on the cylinder and pushed it forward. I only checked one chamber since the cylinder gap was 0.006 - 0.007 for all six. Since I do not have a 0.001 gauge my test is inconclusive. I'm going to use a bright light to look for a gap. If there is no gap, my endshake would match the cylinder gap and be 0.001-002 out of specifications. If I performed this test wrong, please advise.
Before I removed the cylinder I cocked the hammer back enough to examine the firing pin and I noticed that it was flush with back of the mating surface. I used a pin punch to press on it, but it stayed put. I don't know if it means that it was stuck in the case or not, but I have a hunch that it could be. When ignition occurs the case slams back against the recoil shield and the primer pocket locks on to the firing pin. That would definately lock things up if this is happening. Once the cylinder was removed I could push the pin forward and it would retract. Would it be bad idea to apply a tiny drop of thin oil around the pin?
As before, the fired case was easily removed from the cylinder. The case had expanded, but obviously not enough to cause extraction issues.
 

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Cycleman, Here's how you check B/C gap and endshake ..... With an empty gun, wedge the cylinder fully forward and find the thickest blade of a gap gauge that will fit between the cylinder face and the rear of the barrel. This will be your B/C gap. Next, wedge the cylinder fully to the rear then check the gap again. Subtract B/C gap from the second measurement to get endshake. B/C gap should be between .004 to .008". Endshake should not exceed .005" and the cylinder face should never touch the rear of the barrel.

Headspace is measured in a similar manner .... With a factory cartridge or virgin case chambered and indexed under the firing pin, wedge the cylinder to the rear and find the thickest blade of a gap gauge that will fit between the head of the case and the recoil shield, directly in line with the firing pin hole. This will measure actual headspace and should be .010" +or- .002". Next, wedge the cylinder fully forward and measure again. It should not exceed .015"

I think your firing pin is working fine .... primers are detonating and the firing pin retracts like it is supposed to. BTW, you can't push the firing pin forward when the cylinder is locked up because there is no space for the firing pin to move. You can test the firing pin like this ...... With the cylinder removed, cock the hammer then use a tool to push directly on the base of the firing pin .... not on the transfer bar. The firing pin tip should protrude from the recoil shield by about .035". The firing pin should spring back flush (or slightly deeper) with the recoil shield when it is released. I usually push the firing pin at least a dozen times to make sure it isn't hanging up. If you have ever experienced a pierced primer, residue from the primer will blow into the firing pin hole so use a liberal amount of powder solvent to dissolve the residue and push the firing pin in multiple times to flush out the hole. Oil in the firing pin hole is not good .... it will evaporate and turn gummy, making firing pin retraction problematic. Flushing the firing pin hole with powder solvent will dissolve and clean out any sticky oil.
 

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Discussion Starter #14
Iowegan,
Thank you for providing me with your excellent explanation about the correct way to take these measurements, and for the information about checking the firing pin function. I will be measuring again tomorrow.
 

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Cycleman,
AAAARGH! Sorry about the delayed response. Must have missed a notification somehow. Anyway, you said in Post #12 "I cocked the hammer back enough to examine the firing pin and I noticed that it was flush with back of the mating surface." This was done while the cylinder was still stuck. The back of the firing pin shouldn't have been flush with the back of the mating surface at that time. It should have sprung back after firing and it should have been protruding from the frame. You should have been able to move the firing pin forward and have it spring back. Now, the question is WHY? Please check the firing pin operation with the cylinder removed and see if it hangs up or springs back without dragging.
 

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Discussion Starter #16
Wundermech,
After I removed the cylinder I could push the pin forward and it would spring back. I'm going to remeasure the headspace and endshake according to Iowegan's instructions. I had planned on doing it today, but I wasn't able to get around to it. In my #12 post I described my attempt to determine endshake and I also stated that I could not get the 0.015 gauge between the cylinder and the barrel. After reading Iowegan's post, I went back out to my shop and used bright light and magnification and there is zero clearance between the B/C - No Gap! I would think that I should Not be able to move the cylinder that far forward with a couple of pieces of folded paper.
I feel that collectively, we are going to figure this out. During the mean time, I appreciate everyone's comments and contributions, especially yours and Iowegan's.
 

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Discussion Starter #17
Cycleman, Here's how you check B/C gap and endshake ..... With an empty gun, wedge the cylinder fully forward and find the thickest blade of a gap gauge that will fit between the cylinder face and the rear of the barrel. This will be your B/C gap. Next, wedge the cylinder fully to the rear then check the gap again. Subtract B/C gap from the second measurement to get endshake. B/C gap should be between .004 to .008". Endshake should not exceed .005" and the cylinder face should never touch the rear of the barrel.

B/C Gap Measurements: (Empty Chamber)
Wedged @ Recoil Shield end of cylinder: B/C Touch
Wedged @ Barrel end of cylinder: B/C Gap = 0.004"
Not sure if this is relevant regarding Endshake


Headspace is measured in a similar manner .... With a factory cartridge or virgin case chambered and indexed under the firing pin, wedge the cylinder to the rear and find the thickest blade of a gap gauge that will fit between the head of the case and the recoil shield, directly in line with the firing pin hole. This will measure actual headspace and should be .010" +or- .002". Next, wedge the cylinder fully forward and measure again. It should not exceed .015"

Headspace: (New unfired case used for measurements)
Wedged @ barrel end of cylinder: Case/Recoil Shield Gap = 0.002"
Wedged @ RS end of cylinder: Case/Recoil Shield Gap = 0.006"

It appears to me that the fit between the cylinder, barrel, and recoil shield are way off. Could the cylinder be adjusted with a new bushing, or possibly milled a few thousandths to correct the problem?


I think your firing pin is working fine .... primers are detonating and the firing pin retracts like it is supposed to. BTW, you can't push the firing pin forward when the cylinder is locked up because there is no space for the firing pin to move. You can test the firing pin like this ...... With the cylinder removed, cock the hammer then use a tool to push directly on the base of the firing pin .... not on the transfer bar. The firing pin tip should protrude from the recoil shield by about .035". The firing pin should spring back flush (or slightly deeper) with the recoil shield when it is released. I usually push the firing pin at least a dozen times to make sure it isn't hanging up. If you have ever experienced a pierced primer, residue from the primer will blow into the firing pin hole so use a liberal amount of powder solvent to dissolve the residue and push the firing pin in multiple times to flush out the hole. Oil in the firing pin hole is not good .... it will evaporate and turn gummy, making firing pin retraction problematic. Flushing the firing pin hole with powder solvent will dissolve and clean out any sticky oil.
 

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Ruger techs sure didn't do you any favors when it came to fitting the cylinder. Maybe a new guy on the assembly line? When the B/C gap is touching and headspace is too tight, the gun just isn't going to work well, especially with hot loads. If it were my gun, it would be taking a trip back to the factory to have a new cylinder fitted properly.

B/C gap way too tight.
Headspace too tight
Endshake???? probably too loose .... hard to say because the cylinder contacts the barrel.
Could the cylinder be adjusted with a new bushing, or possibly milled a few thousandths to correct the problem?
No, headspace is regulated by the ratchet column and yours is too short. Shims/bushings don't work on the rear of the cylinder because of the pawl slot in the frame. The only way to extend the ratchet column is with a new cylinder

Besides the hot loads, no doubt the misfit cylinder is the main problem. That said,
if you are going to shoot Ruger Only loads, at least get some decent powder like W-296 or H-110.
 

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Cycleman,
This is disheartening news. I have no idea what the most economical cure is. If the consensus is a new cylinder needs to be purchased and fitted, I’d be really tempted to put the existing cylinder in the lathe and face a few thousandths off the back of the cylinder where the chambers are first. This wouldn’t change the end shake or the zero B/C clearance, but it would increase the headspace. Maybe that will be good enough. I also wouldn’t touch the barrel without at least seeing how your 45 ACP cylinder checks out. My guess is that this corrective measure is probably way more work than most people would consider reasonable. If you’re feeling brave after that and want to punish yourself a little more, you could also face a few thousandths off the front of the cylinder to increase the B/C clearance, but you run the risk of increasing endshake if the barrel is what’s holding that in check right now. Iowegan - please double-check my logic to make sure I’m not spewing a bunch of crap!
 

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Discussion Starter #20
Thanks, fellows, for your assessment, comments, and advice. Of course I'm not happy with this situation. The first thing I'm going to do is check the ACP fit. Next, I'm going to call Ruger and lay out my case with them and see how receptive they are to correcting my defective gun.

Iowegan you stated:
"No, headspace is regulated by the ratchet column and yours is too short. Shims/bushings don't work on the rear of the cylinder because of the pawl slot in the frame. The only way to extend the ratchet column is with a new cylinder."


I understand your statement above except foe the part about the ratchet being too short. How can it be short when it seems to me that I have a situation where the cylinder is being crammed in between the barrel and the recoil shield. With the cylinder and barrel touching and very little head space, how can the cylinder be short? I am not questioning your assessment at all - just trying to understand the mechanics of all this.

Is the ratchet column an integral part of the cylinder? If it is, was this a result of a milling mistake by reducing the length of the ratchet column? Based on what you stated, it sounds like this is the key to fitting the cylinder properly. As for the B/C gap, I'm thinking this must be fitted last by facing off the barrel once it has been installed to get the proper gap.

I thank you again for sticking with me on this.
I'll let you all know how it all plays out!

I
 
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