Ruger SA cylinder rotational play - acceptable tolerances?

[Toni]

Hi, I searched and read all I could find about the subject but didn't find any exact numbers. Usually what is said is "little is ok, much is too much".

Ok, so I have 4 Ruger single actions and one of them has bigger play than others. My Blackhawk .357 Mag from 1984 has clearly more than its younger siblings (all from 90's). Long time ago when it was easier to get parts from USA to Europe I bought a oversize basepin and oversize cylinder latch for it. I installed the basepin but never the latch. Now, I am thinking about it again. But then I also started thinking that do I really need it? How to determine if the play on the BH is still ok or outside of what is considered acceptable? And how to measure it?

Edited for clarity: Another thing - With the oversize base pin in place the forward-aft play is almost zero. And I can fit a 0.15mm (0.0059") feeler gauge between the cylinder and barrel (it feels tight).

I have not shop paper with this gun but seem to hit steel figures as well as with any of the others.

Comments?

 

[mirglip]

I'm no gunsmith but I understand that the latch is a timing part that should be individually fitted by a gunsmith.
Often that kind of cylinder play is a sign of high round count, and sometimes if a gun comes from the factory with poor timing, the bullet side slams the forcing cone and causes that slop to increase faster.
I have heard of people using a hammer and punch to peen the frame on one side of the latch or the other to take up slack or adjust timing.

Almost all of the 18 Ruger single actions I have owned, the cylinder gap was right at .003" and I don't recall any with more than .0045" (most were chambered .22LR) so I think your cylinder gap is slightly excessive, another sign of high round count.
Generally the single actions made before 1985 were put together a little better than later ones. I suppose you could just replace the latch and see how it shoots, as good revolver gunsmiths are hard to find even here in the US.
Have you checked the gap with the feeler gauge on both sides to see if they are different? I had a Smith and Wesson with .002" difference and it was not very accurate.
Probably someone with more knowledge will chime in with better advice.

 

[contender]

We;come to the Forum Toni!

Ok,, if I correctly read your post,, your discussing the "play" or movement forward & aft of the cylinder. Your title says "rotational" play so I may be wrong here.
The fore & aft play,,or as we commonly refer to it as "cylinder gap" measures .0059, (0.15mm.) If this is a centerfire,, that's NOT too large or uncommon. And the base pin doesn't do anything to correct this. The base pin is not used to shorten (or lengthen) the gap.

BUT,, the rotational play,, of when a cylinder can be manually moved in either direction of rotation is the job of the cylinder latch.
When the gun is fully cocked,, in a Ruger,, most often,, there is going to be a very small amount of general rotational play. that is part of how the gun was designed. It's there to allow "mass production" and when firing,, it allows the bullet to "shift" the chamber exit hole to align the bullet with the throat & bore.
A true precision built SA handgun,, is often "line bored" for cylinder alignment,, AND the latch is also tightly fitted. This costs more money & since Rugers are mass produced,, they do not take this route during building them.
As for "excessive" rotational play,, that's a very subjective thing quite often.

The first thing I would do is to seriously shoot the gun at a distance of at least 25 meters, on paper,, and see how well it groups. And,, have a friend,, who is a known good shooter do the same thing. A minimum of 2 cylinders full of ammo by each of you on one target each. That will tell you if the gun is not performing as well as you think it should,, OR,, it may show you that you may not have any worries.

Another little easy trick is to take a square cardboard box. Remove the top & bottom of the box. Use a box just big enough to get your gun & hands inside it,, or at least just the cylinder & barrel. Fire a few cylinders full, and then look at the inside "walls" of cardboard. Look for small bullet fragments,, or unburnt powder stuck to the cardboard. Use cast bullets for this too.
If the cylinder is out of alignment too much,, then you will get tiny shavings from the gap where the cylinder meets the barrel. A term called "lead shaving."

You did mention shooting the gun at steel & doing ok. The gun may just feel a bit "looser" than your other guns,, but may be a perfectly fine handgun. Or,, it may well be in need of a proper adjustment.
Just remember,, a Ruger was built with looser tolerances than a custom built gun, and can feel "off!"

 

[Toni]

Often that kind of cylinder play is a sign of high round count

Thanks for your comment.

Almost all of the 18 Ruger single actions I have owned, the cylinder gap was right at .003" and I don't recall any with more than .0045" (most were chambered .22LR) so I think your cylinder gap is slightly excessive, another sign of high round count.

The Ruger Shop manual says this:

 

[Toni]

Ok,, if I correctly read your post,, your discussing the "play" or movement forward & aft of the cylinder. Your title says "rotational" play so I may be wrong here.

No, I mean rotational play. I just added the detail that I have measured the forward - aft play and the result I got. I saw many people mention the base pin in various threads discussing play so I thought I mention it too. ;)

BTW. I just checked my low shot count Vaquero and its cyl to barrel gap is very similar. I can insert the same feeler gauge and its very tight. But, it has bigger end shake than the old BH! I mean if the end shake is the correct word for the forward - aft play?

BUT,, the rotational play,, of when a cylinder can be manually moved in either direction of rotation is the job of the cylinder latch. When the gun is fully cocked,, in a Ruger,, most often,, there is going to be a very small amount of general rotational play. that is part of how the gun was designed. It's there to allow "mass production" and when firing,, it allows the bullet to "shift" the chamber exit hole to align the bullet with the throat & bore.

Yes, this is perfectly clear to me.

I'll read your reply with thought and get back soon.

 

[Toni]

The first thing I would do is to seriously shoot the gun at a distance of at least 25 meters, on paper,, and see how well it groups.

Yes, I'll need to do this before doing anything else.

Another little easy trick is to take a square cardboard box.

This is a good idea, didn't think of that! (y)

You did mention shooting the gun at steel & doing ok. The gun may just feel a bit "looser" than your other guns,, but may be a perfectly fine handgun. Or,, it may well be in need of a proper adjustment.
Just remember,, a Ruger was built with looser tolerances than a custom built gun, and can feel "off!"

Yes, it does feel looser on the rotational play. And I only have Ruger SA revolvers so I am comparing to those only. No custom revolver stuff here.

Like I said what I am trying to find out is that how do I determine if the amount of play is fine or not? The cardboard box -method will tell me about the alignment but any figures on how much the cylinder can move side to side and still be considered normal?

And how to measure it? I do have a dial indicator but I need to rig some kind of jig or thing where I can eliminate all possible variances when measuring. If there is easier way then I am very interested.

 

[arfmel]

I believe I would shoot the gun at a target and see how accurate it is. You may find that it’s better than another one with less play.

 

[contender]

As I mentioned,, and mentioned above,, shoot it first. the final word on any gun is the target. it tells the story. As least,, it does if the shooter is capable.
I have seen people who just could not shoot a handgun. They'd hand me to gun saying it was inaccurate. Yet,,I'd easily shoot a nice tight group,, and point out that they needed to learn to do correct pistol practice on HOW to shoot.

That said,, it does sound as if you are a capable shooter,, so the cardboard box will allow you to see if there is lead shaving etc.

As for how to measure the rotational play,, I'm not sure I can recall anyone measuring that. So I can't help there.

If you do replace the cylinder latch,, the first thing to do is compare the results of accuracy in a comparison between the "before" and the "after" installation. And you may well want to do the box test as well after you replace the latch.

 

[Toni]

As for how to measure the rotational play,, I'm not sure I can recall anyone measuring that.

Yes, I cannot seem to find any clear specs on this matter. The Ruger Shop Manual is a bit difficult read as there is so much stuff in it and spread in many sections of the book, so I didn't find any there either. I find this little weird as pretty much everything else seems to have clear numeral specifications but not this, it is always "very little" or "little" is good and "too much" is not good. Doesn't really help in real world. ;)

I am sure in USA I could just show it to a gunsmith or some other Ruger gunslinger and he could tell me his opinion on the play. But here, I have never seen another guy with a Ruger at the range. I am sure there are thousands of Rugers around but... :oops: Hmm... maybe I should attend a CAS event, there should be some?

And I don't know of any gunsmiths who today would know anything about Rugers. 20+ years ago there were some I knew but they are not available anymore. For future needs I should ask around, there must be somebody who knows his stuff.

But, as said I need to verify the accuracy on paper and compare it to the others. If ok then I will not do anything more at this point.

Thank you all for your advice. (y)

 

[mirglip]

Both the manufacture and repair of revolvers requires much more skill than the manufacture and repair of semi-autos. For that reason you can't find many good revolver gunsmiths here or anywhere. Why would a guy with that much talent want to compete with mass production? Most likely you will have to muddle through your problem by yourself.

 

[Toni]

Yeah, that might be the case. Well, I'll figure things out if necessary.

Gunsmithing is one of those professions where more old guys retire than new guys enter to replace them. And it might take years-decades before the new guys are proficient on the same level than the old smiths - if ever. Very difficult to find anybody to do anything these days. And if you find one they have year or more of backlog. Same thing with other high skill manual work professions like for example tape deck repair guys or watchmakers.

 

[RoninPA]

My .02 cents (but the US just stopped producing the 1 cent piece so.....)

For a quick CW/CCW rotation check, unload the gun, rotate the cylinder until it latches into place (hammer down), and rotate the cylinder back and forth with your fingers and see/feel what it does. Then cock the hammer and then hold the hammer so it doesn't go forward and pull the trigger (this is what I was taught but some say you can let the hammer release and go forward. I've tried it both ways and can't discern any difference so it's your choice). While holding the trigger back and not releasing it, again try to rotate the cylinder and see what it does. Doing this this way locks all the parts as when you fire a round and if the cylinder rotates more than what you feel would be normal, then you would want to look at both the cylinder notches and the cylinder latch for any wear.

 

[larry8]

Ah, RoninPA beat me too it. But that is the way to check the rotational movement in any revolver. I was taught that way a great many years ago by a very good gunsmith. Since that time I have bought and sold a great many revolvers and that is the way I check each one when I buy them. As far as the "normal" amount it is very little when done that way, any noticeable amount would be "too much" and I'd walk away from that gun.

 

[Toni]

My .02 cents (but the US just stopped producing the 1 cent piece so.....)

For a quick CW/CCW rotation check, unload the gun, rotate the cylinder until it latches into place (hammer down), and rotate the cylinder back and forth with your fingers and see/feel what it does. Then cock the hammer and then hold the hammer so it doesn't go forward and pull the trigger (this is what I was taught but some say you can let the hammer release and go forward.

Well, this is what I feel in various positions:
- gun uncocked: there is play
- gun cocked: same amount of play
- gun cocked and trigger pressed, not letting hammer strike: same play
- gun cocked, trigger pressed, hammer down: again same
- gun cocked and holding the hammer in most rearward position with thumb: zero play. The pawl is now fully engaged and removing all play.

Other observations:
- cylinder notches seem fine, miniscule wear only, cannot be seen with naked eye
- the cylinder latch has considerable side movement in the frame notch, when the pawl is not fully engaging the play comes from here. The frame notch seems to be in good condition and I do not see obvious damage to the latch either. Is there a way to tighten or shim the latch for less play?

So, now I am wondering about the role of the cylinder latch and pawl in conjunction of cylinder play? Are they both responsible for locking the cylinder and removing play or the latch only?

I rummaged through my spare parts bin and I have a new trigger, pawl and hammer. I do not have a stock cylinder latch, only the Power Custom oversize one. Also bunch of springs and pivot pins.

 

[RoninPA]

No, the pawl's only use is to rotate the cylinder to the next position. In SA mode, when you pull the hammer back to cock it, when it gets to the full rearward position and you release your thumb from it , it will move forward a tiny bit and the pressure on the pawl gets released and the pawl spring forces the pawl towards the back to clear the cylinder ratchet. The cylinder latch pops up into the cylinder notch while this is going on and it alone locks the cylinder. When you pull the trigger the cylinder latch stays in place until the trigger is released and as it goes forward then the cylinder latch drops down into the frame so the cylinder can rotate with the next pull of the hammer.

Now, the amount of movement in the cylinder when you do what you did is VERY subjective. That is why most will say to try shooting it within a close fitting box to see if there is any lead shaving from the cylinder moving slightly out of alignment if the latch itself or the latch cut of the cylinder is not correct. If you have or can get hold of a half dozen or more Ruger SA's (new and used) to perform the above tests that will help build a knowledge base and a feel of what the rotation should feel like. If you can get hold of one that is older and has been shot a lot (or I hate to say, abused), I think you would be able to tell the difference pretty quick.

 

[Toni]

No, the pawl's only use is to rotate the cylinder to the next position.

Ok, thanks. That clears it up. It was what the shop manual calls hammer "overtravel" when the cylinder gets "pinched between" the pawl and the latch where there is absolutely no play at all. But, I guess it is logical that when the the hammer is released from overtravel position the pawl moves slightly away from the cylinder which is then held in position by the cylinder latch. Just wanted to check that as I remember reading that some revolver actually had the pawl also steadying the cylinder but that was not a Ruger but some older stuff.

Now, the amount of movement in the cylinder when you do what you did is VERY subjective.

Yes it is. That is what I have been complaining about. ;) Nobody can turn that into numbers which makes it a bit difficult.

If you have or can get hold of a half dozen or more Ruger SA's (new and used) to perform the above tests that will help build a knowledge base and a feel of what the rotation should feel like.

That is pretty much where I started this thread. I have 4 Ruger SA's and 3 of them are tighter than this one. And I know absolutely no other person in this country with a Ruger revolver so slim chance of getting any more to compare with. So, my knowledge base is purely based on 4 revolvers, 25+ years of owning them, the shop manual and the more experienced internet people. ;)

If you can get hold of one that is older and has been shot a lot (or I hate to say, abused), I think you would be able to tell the difference pretty quick.

Well, this one is the oldest one and probably also the most used one. But, it has no other visible wear marks than the rotational play (and some nicely worn bluing). Even the end shake is less than what my low shot count Vaquero has.

Still the paper shooting and box test too to come at some stage. Then maybe a test fit with the new cylinder latch to see if that is doable by myself. But I need to find a range rod gauge of some kind that fits properly and does not cost too much. Improvised self made gauge preferable over the $80 commercial ones.

 

[RoninPA]

In my opinion, it sounds to me that your rotational movement is probably ok. To get really "sloppy" really takes some work on the shooters part (heavy loads, trying to shoot it as fast as possible for many rounds, etc.). I have Rugers that are pretty darn old (both SA's and DA's) but have not been abused (normal routine shooting, etc.) and they do move a little bit. But since revolvers will "loosen up", over time, just due to use, I know that they aren't out of spec and they shoot fine with no lead spitting.

 

[contender]

Without actually being able to feel & see your revolver,, I tend to agree with Ron about your gun being pretty much "ok" & normal. That's why I suggested the box test.

Give it a try & report back!

 

[DGW1949]

Measuring rotational play?....That's a job for a dial indicator, but good luck on finding the factory spec for that.....I've changed a latch or two due over the years due to their sides becoming visibly worn. In fact, my old 3-Screw .357 is on it's third latch as we speak....It's also on it's second cylinder "bushing" and cylinder pin...Strong guns, but not the "tanks" that some make them out to be.

DGW

 

[Toni]

Measuring rotational play?....That's a job for a dial indicator, but good luck on finding the factory spec for that...

Yes, I have the tools but not the spec like we concluded above so some further testing is in order and then if necessary the new latch. I will report back when I have a chance to do the tests suggested.