How much play in a revolver cylinder?


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Beatnik
November 19, 2007, 04:03 PM
I bought a used GP100 last summer. It was a police trainer and was probably beat up pretty good.

Originally I could lock it up, wiggle the cylinder, and I could hear that there was play, but not see it move.

I put about 10 magnums through it, and a bunch more spcl and +P, but probably only around 60 rounds total.

I also replaced the hammer spring afterward, took it down to 10 lbs.

Now, I can see the cylinder moving. It's not swinging wild, but it is moving more than a few thousanths. Is this something I should get checked out and fixed?

(Also, anyone recommend someone in the NoVA area?)

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Fumbler
November 19, 2007, 04:30 PM
Did you clean the gun?
If it was dirty and you cleaned it then it may lock up just a hair looser because there's no dirt to hold it as tight.

A tiny bit of cylinder rotation on lockup is normal (and preferable).
If it moves a few hundredths then you might want to have it looked at.
If it moves, but turns back to its original position, then it is fine.

On the other hand, if it moves forwards and backwards (not rotating) more than a couple thousandths then bring it to a gunsmith.

Beatnik
November 19, 2007, 04:55 PM
The guy that sold them bead blasted them before sale (they're stainless).
If anything, it's dirtier than it was, since I haven't gone crazy on it with a brass brush or anything.
There's 0 back-and-forth... but I'm wondering, why would a tiny bit of rotation be preferable?

I haven't looked through the bore to see if I can see the cylinder face, I'll try that tonight.

Fumbler
November 19, 2007, 05:00 PM
In a perfect world (of if you have enough money) the cylinders would line up perfectly with the barrel.
Most revolvers do not line up perfectly. Close, but not perfect.
Having a tiny bit of play allows the bullet to push its way into the barrel easier.
Really tight lockup and off center chambers could result in bullets shaving on the edge of the forcing cones and poor accuracy.

dfariswheel
November 19, 2007, 11:33 PM
The only DA revolvers that lock up tight when the trigger is pulled are the old Colt models like the Detective Special and Python.
Colt was famous for their "Bank vault lockup".

All other brand of DA revolvers, including the Ruger, intentionally allow the cylinder to be slightly loose when the trigger is pulled.
This allows the bullet entering the barrel to force the cylinder into alignment.

The old Colt was tightly locked in perfect alignment, but this requires a lot of hand fitting which is expensive.
Other brands allow the cylinder to be slightly loose, which is a faster and cheaper action to build.

Therefore, your Ruger MUST have some movement in the cylinder to allow it to function properly.
There is no factory standard as to how much movement is allowable, the only test is how accurate the gun is, and is it mis-aligned and "shaving" lead.

tiders
November 29, 2007, 08:13 AM
Hi! Bumping this thread.

Just how tight should this lock-up be in a Python? I have one and the cylinder moves maybe a millimetre. I just bought it and the seller said “well it’s no S&W...” I thought Colts were tighter than smiths? It’s no more tight when I cock the hammer than when its “hammer down”.

Also, I don’t know if there is a connection, but last night I fired 50 rounds of mild .38’s and had 3 misfires. I fired double action and all the primers had dents in then. From the striker pin I guess. The marks were on the right hand side of the primer.

dfariswheel
November 29, 2007, 08:35 PM
The Python should lock up tightly WHEN THE TRIGGER IS HELD BACK.

Simply pull the trigger on an EMPTY revolver, and HOLD the trigger back.
Attempt to rotate the cylinder, and it should be firmly locked in place with no movement.

Of course, recognize that if you use any force you will be able to force the cylinder to move slightly.
Just gently attempt to rotate the cylinder.
If there is any movement, the revolver needs repair.

If your revolver is mis-firing in double action, in all likelihood, someone has bent the mainspring in an attempt to "improve" the trigger pull.
The classic sign of this is mis-fires in double action.
The "fix" is to simply replace the mainspring.

Of course, check for a broken or chipped firing pin.

If the firing pin strikes were off-center, there's a strong possibility your Python is "out of time" or not locking up properly.
In this case, the gun is actually firing in an UNLOCKED condition.
If after the following checks, you determine the gun is not locking up properly, STOP SHOOTING IT, until it can be repaired.

In order to help you check your Python for proper operation, here's my instructions on how to check the Python's timing:

BOLT RETRACTION AND "SNAP BACK".
Open the cylinder and look at the small "lug" in the bottom of the cylinder window. This is the cylinder locking bolt.

Cock the hammer, and watch as the bolt retracts into the frame and pops back out.

The bolt MUST begin to retract THE INSTANT the hammer begins to move.
There MUST be NO (ZERO) hammer movement possible before the bolt starts to retract.

The bolt should retract smoothly with no hesitation until it's fully retracted, then it MUST pop back out with a clean "snap".
There should be no hesitation, and no amount of "creeping" back out.

CYLINDER UNLOCKING.
Close the cylinder.
Use your left thumb or fore finger to again cock the hammer, closely watching the cylinder bolt as you SLOWLY cock the hammer.

As the hammer comes back, the bolt will retract away from the cylinder.

The bolt MUST retract far enough to unlock the cylinder BEFORE the cylinder begins to rotate.

If the bolt is still slightly engaged with the cylinder lock notch, the cylinder will be attempting to turn while still partially locked.

This produces a "catch" or "hard spot" in the trigger pull and will damage both the bolt and the cylinder lock notches.
This often appears as metal "pulled out" of the lock notches, with rounded off and burred notches.

BOLT DROP TIMING.
Continue to cock the hammer, laying your right index finger on the cylinder just enough to prevent "free wheeling".

Watch for the bolt to drop back onto the cylinder. WHERE the bolt drops is CRITICAL.

The bolt MUST drop onto the lead or ramp in front of the actual cylinder notch.
If the bolt drops too soon, (in front of the notch ramp), it will mar the finish of the cylinder.

The bolt SHOULD drop into the MIDDLE 1/3rd section of the ramp.

If the bolt drops late, (farther toward the actual locking notch) the revolver may display "cylinder throw-by".
In this condition, during double action shooting the cylinder may rotate PAST the locking notch, and fire in an unlocked condition.

It's the nature of the Colt action, that a hesitant or jerky trigger pull by the user can induce throw-by in even a properly tuned Colt.
The Colt trigger should be pulled with a smooth, even pull, with no sudden jerks at the beginning.

CYLINDER LOCKUP.
Continue to pull the hammer back and both watch and listen for the bolt to drop into the cylinder lock notch.

The bolt MUST drop into the actual lock notch BEFORE the hammer reaches full cock.

The most common Colt mis-time situation is the hammer cocks before the bolt drops into the lock notch. (Hammer is cocked, but cylinder isn't locked).

In this condition, with the hammer fully cocked, you can push the cylinder slightly, and you will hear the "CLICK" as the bolt drops into lock.

In my experience, most Colt's leave the factory with the bolt dropping a little late into the lead, but usually wear in to correct timing.

If the bolt drops onto the cylinder early, no real problem, but there will be extra finish wear.

If the bolt drops late (closer to the lock notch) the cylinder may "throw by" or rotate TOO far in double action and this can cause off-center primer hits and firing while unlocked.

Each of these checks should be done on EACH chamber. All of these checks are better done individually. In other words, do the bolt retraction check on all six chambers, then do the bolt drop test, and so on.

A properly tuned Colt will:
Have a smoothly functioning bolt with no sticky or hesitant movement.

Unlock before the cylinder begins to turn.

The bolt will drop onto the middle 1/3rd of the ramp.

The bolt will drop into the lock notch before the hammer reaches full cock.

Have a smooth trigger pull, which does "stack".

NVMM
November 30, 2007, 12:57 PM
dfariswheel, Thank You
Always informative Posts.
Michael

tiders
December 10, 2007, 06:12 PM
dfariswheel, thanks a million.

I've been without a computer for a while. Sorry for this late note of appreciation. I will check the points on your list.

/T

DogBonz
December 10, 2007, 06:25 PM
see here:

http://www.grantcunningham.com/blog_files/colt_python_delicate.html

This is a good read for any Python owner, or anyone who thinks that they are delicate.

-Fred

tiders
December 10, 2007, 06:41 PM
Thanks DogBonz, I saw that one and enjoyed it. There is a lot of theory regarding the fragility of these gems.

I live in Norway and there isn’t too much help in the shops. I suppose the marked for Pythons always was rather limited here... I always end up searching sites stateside, thanks for the tip.

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