Cylinder shake comparison, Python and K-22

[Ailog]

I have a Python that I bought new in '83. Only has about 500 rounds thru it and mostly .38 spl. I also have a '48 K-22. Now the Python measures .0015 cyl to barrel with cyl forward and .007 with cylinder back. With full lockup the cylinder is forward and is rock solid. The K-22 has almost the same readings (.002 with cyl forward and .008 with cyln back). The Python shoots well and has no problems.

Now my question is about the K22. I am wondering how is it possible to get that much shake, if it is indeed excessive. The cyln doesn't lock up like the Python so it can bang around more when fired. But its hard for me to believe that it banged itself into that clearance. The K22 shows moderate wear for its age. There is no crane slop whatsoever and I don't see any obvious wear on the rear of the cyln or the frame area. Is it possible that the K22 clearances that I am seeing are not to far off of when the gun was new? The clearances are consistant for each chamber position and I don't see anything else out of sorts.
Thanks

 

[Standing Wolf]

The Python's hand pushes the cylinder forward during lock-up. The K frame's doesn't.

On the whole, Smith & Wesson revolvers have more play than Colts. It doesn't necessarily mean they're less accurate: merely that they follow a different design.

 

[Ailog]

Thanks for the reply Standing Wolf. Looks like you have been on the forum for awhile. I just found about a month ago and have enjoyed reading thru the archives.

 

[dfariswheel]

The Colt's hand does push the cylinder forward, BUT when fired, recoil pushes it right back.

On all revolvers, end shake is measured with the action un-cocked and at rest.

The factory spec for the Colt is .000" to a Max of .003".

S&W has a wider spec of a .001" to a Max of "about" .006", OR if the cylinder is contacting the barrel.

 

[GrantCunningham]

I have a Python that I bought new in '83. Only has about 500 rounds thru it and mostly .38 spl. I also have a '48 K-22. Now the Python measures .0015 cyl to barrel with cyl forward and .007 with cylinder back. With full lockup the cylinder is forward and is rock solid. The Python shoots well and has no problems.

Colt specs for endshake (the fore-aft movement of the cylinder that you've noted) is "less than .003". I've found even that amount may be a bit excessive.

What happens is that when the cylinder moves rearward under recoil (while the ratchet is contacting the hand) the hand is subjected to both sliding (abrasive) and compressive forces. These combine to accelerate wear on the hand, which eventually results in an out-of-time condition.

I've found that setting endshake to no more than .002" for a carry gun, and .001" for a target gun (with a properly fitted hand of course) results in better timing life.

Any endshake over .003" is definitely cause to have the gun visit a qualified smith.

 

[Ailog]

<<The factory spec for the Colt is .000" to a Max of .003".>>

Thanks for your reply. Is that saying the cyln/barrel clearance with the cyln forward can be up to .003? Or is that saying the cyln shake or max. movement can be no more than .003? Cylinder movement in the uncocked position would normally have to be greater than .000 to allow for expansion.

 

[Ailog]

Colt specs for endshake (the fore-aft movement of the cylinder that you've noted) is "less than .003". I've found even that amount may be a bit excessive.

Thanks for your reply. My Colt is has very low milage and the gun came with the cyln movement that I have mentioned. I am going to compare it with some other pythons that I know are for sale and I can inspect.

Also, during lockup the cylinder is dead solid and applying some pressure it cannot be moved to the rear. This leads me to believe that when fired the cylinder will stay where it is as I don't believe Colt would design the system that would force the cylinder back against the pressure of the locking bar.

 

[Old Fuff]

I have found older S&W revolvers with cylinder/barrel gaps that were as little as .003" and as much as .009". Older revolvers tended to have wider gaps because of the use of soft lead bullets that would spatter both the cylinder face and the back end of the barrel with lead - which could quickly close a tight gap.

The more important question is, "can all chambers pass a test with a range rod, that determines the concentricity between the bore and chamber(s)?" If so a slightly wider gap doesn't seem to have much practical effect on accuracy, while a too-tight gap may cause the cylinder to bind.

 

[dfariswheel]

Ailog:

Place a FIRED, UNPRIMED case in a chamber. (De-prime first to prevent any firing pin cratering in the primer from giving a false reading).

Rotate the cylinder so the empty case is lined up with the bore.

Push the cylinder to the rear, and use a feeler gage to measure the gap between the case and the breech face at the firing pin hole.

Then push the cylinder forward and measure again.

The difference is end shake.
Total end shake over .003" is out of spec.

"during lockup the cylinder is dead solid and applying some pressure it cannot be moved to the rear. This leads me to believe that when fired the cylinder will stay where it is"

Sorry, that's wrong.
There's a whopping difference between pushing a cylinder by hand, and firing a live round.
It IS the cylinder being slammed first forward, then back under recoil that causes end shake, and it's that slamming back and forth that will wreck a good revolver if excessive end shake is allowed to continue.

The "locking bar" is actually the "hand" that rotates the cylinder, and in Colt's case, locks it during trigger pull.
The hand is held forward under mere spring pressure from the mainspring.
Recoil WILL push it back.

The bottom line here, is that the Colt revolvers have a tighter spec for end shake, and when it gets over the spec, a smart owner gets it fixed before the gun gets battered.

 

[Ailog]

Thanks for the reply Old Fluff. Interesting about the gaps on the older revolvers. I have done some preliminary alignment checks on the bore and cylinder chambers on the S&W, but I will next do the range rod check.

 

[Ailog]

The "locking bar" is actually the "hand" that rotates the cylinder, and in Colt's case, locks it during trigger pull.
The hand is held forward under mere spring pressure from the mainspring.
Recoil WILL push it back.



dfariswheel
As you suggest I will try the unprimed fired case gap test next on the python and see what I get. I'm working with old feeler gauges!

Here is what I am seeing during lockup. As the trigger moves fully back, the cylinder stop rises up from its "normal" position and presses hard against the cylinder. The movement is slight but I can definitely see it, and can also feel the very slight cylinder reaction. So on this gun it appears to be what is aiding holding the cylinder rigid. I tried looking if I could somehow detect the rotating "hand" move forward but its hard to see with the cylinder closed. I am not an expert on pythons (or Colts). I've had this gun for quite awhile and am just recently giving it a close exam. I should probably try to get a schematic on it to learn more.

 

[Ailog]

dfariswheel
As a follow up, I was able to see the rotating hand move forward during lockup and as you say it is under spring pressure.

 

[unspellable]

Cylinder end play

Different revolvers, different designs. In the python the hand pushes the cylinder forward at lock up and eliminates the end play. But as mentioned above, on firing the spring force on the hand will be over come and the cylinder will move. This actually the weak point in the Python design that makes them famous for going out of time.

On the S&W the weak point is the use of the yoke tail to limit forward movement of the cylinder as it has a very small bearing surface.

On firing, the cylinder is forced FORWARD, not rearward, and the principal wear will be at the yoke tail. The cylinder will then bounce back, and that's when the Python's hand takes a beating, and it's a delicate and closely fitted part.

Now my big question is, what's the proper end clearance for a Dan Wesson? This is a more complicated picture because the cylinder is held forward under fairly stiff spring tension by the ball detent at the rear of the cylinder, so it does not get the chance to run forward. The end play is zero if measured without compressing the ball detent. The srping is stiff enough to provide some cushioning if the cylinder goes to the rear.

 

[Ailog]

unspellable

My python actually locks up by the cylinder stop lug rising up from its "normal" position when the trigger moves rearward. This is after the hand pushes the cylinder forward. So on lock up the cyln is forward and pretty much immobile. The cyln stop presses hard up and the cylinder cannot be moved. The trigger in the rearward position holds the cylinder stop hard up. The stop also cannot be moved downward and is not spring loaded in this position. This is also evidenced by seeing no travel makings on the cylinder from the cylinder stop as would be seen if the cylinder tried to move with the stop pressing hard on it during firing. The next time I shoot it I am going to see what I can see about any cylinder movement. This is the only Colt I own so I am not familiar how other Colt models do it, but from what I read the python may be unique in how it locksup.

 

[unspellable]

The Python

The Python is not unique among Colts in its lockwrok design, but it is on of the last if not the last remaining Colt with the older lockwork design. When cocked, the hand tip pushes on the ratchet to rotate the cylinder. After being cocked the hand tip continues to bear upward on the pawl. (Unlike a S&W or later design Colt.) When the trigger is pulled the hand rises a bit further and if porperly timed, pushs the cylider around as far as the bolt will allow, creating that "solid' cylinser feel. Unless you have a very unusual Python the bolt wil ldo nothing to limit cylinder movement in either the fore or aft direction, only in the clocwise rotation direction. At this point the hand will limit counterclockwise rotation. (Here is the difference, later Colts, S&W's, etc., limit cylinder rotation in both directions with the bolt.) The rather delicate and precisely fitted hand tip then takes a hammering when the revolver is fired.

The python I should not advise,
It needs a doctor for it's eyes
And has the measles yearly.
But if you should find,
You want one to improve your mind
And not for fashion merely,
Allow no music near its cage
and if it flies into a rage,
chastise it most severely.

I had an aunt from Yucatan
Who bought a python from a man.
She died, because she never knew
These simple little rules and few.
The snake is living yet.

 

[Ailog]

Unspellable

Very interesting discussion. I now see the error of my ways. It is deceptive. After the hand moves the cylinder to the next position, one would think that the hand moves no further. But as you say, as the trigger is pulled the hand moves up a little bit more. What was fooling me was that the cyln lock lug is spring loaded and will move if the cyln moves a little. Thus it appeared that the cyln lug was pressing up on the cyln vis the trigger action.

So it appears that the extra hand movement when the trigger is pulled serves to snug up the cylinder against the clyn stop lug. I can visually see the cyln rotate a tiny bit taking up whatever slack there is. It would seem that the timing would have to be spot on for this to improve accuracy since that last tiny bit of cylinder movement from the hand when the trigger is pulled would have to result in the best alignment of the cyln and barrel?

Anyway, I should thank you and all the guys that responded to my posts to try to explain this to me. But I am a hard head and have to learn by experience. I like the poem too. I have owned many types of firearms over the years and have always tried to figure out how they work. But as you know sometimes it requires serious study.

 

[unspellable]

The older Colt lockwrok

There you have it. When every thing is absolutely spot on the older Colt style lock work will produce better alignment than say a S&W. But the drawback is that it requires careful spot on hand fitting and is somewhat delicate and prone to going out of time as compared to the S&W.

The Webley Mk VI is an example of a revovler design that locks the cylinder even more rigidly than the Colt and is also more durable than the Colt. The Webley never caught on here because it isn't "pretty" like a Colt or S&W.

I suspect the "prettiness" factor is what sells the Python as much as anything.

 

[Ailog]

I am going to a gun show tomorrow and I will be interested to see any Webleys and have a closer look. I bought the Python new in '83 and I can't remember what the major attraction was. I think the feel of the gun and the action probably more than anything else. At that time I wasn't aware of the guns performance or model history. It still feels right.

 

[unspellable]

Webleys

In the last two or three years I have not seeen a good Webley at a gun show, only old beaters that had really been hammered and abused.

 

[Ailog]

I looked at a couple this past weekend. The cylinders were very loose left and right until lockup, then it was snug. Like anything, you have to look at quite a few to get an idea of what to expect.

 

[unspellable]

Webley

The Webley Mk VI cylinder should have afair amount of rotatiuonal play when at rest. This play should be reduced when cocked and eliminated when the hammer is down and trigger held back. In that condition it should feel like the cylinder is spot welded in place. Hamme down and trigger back is the proper way to evaluate the cylinder's rotational play on a Webley Mk VI.

 

[Ailog]

unspellable
The ones I looked at exhibited what you are saying. I even looked down the barrel of one with hammer down and trigger back to see how well the cylinder chambers lined up with the barrel. The barrel is wide enough that I could do it and see down. I moved the cylinder one way and the other before I brought the trigger back to see if the cyln would go into the same position when it locks up, and it did. So I am learning as I go. Thanks for the info., very valuable!

 

[unspellable]

down the barrel

That's a good test for alignment on any revolver. I carry an extremely thin penlight by Streamline for the sole purpose of looking down revovler barrels. One should look at all chambers, not just one. I view this as a better test than sticking a range rod down the barrel and you don't have to have a rod for each caliber.

Just be D**N sure the revolver is unloaded!

 

[unspellable]

down the barrel

That's a good test for alignment on any revolver. I carry an extremely thin penlight by Streamline for the sole purpose of looking down revovler barrels. One should look at all chambers, not just one. I view this as a better test than sticking a range rod down the barrel and you don't have to have a rod for each caliber.

Just be D**N sure the revolver is unloaded!