[Michael]

So, I understand that a little endplay is okay... too much a bad thing. But, how can I tell the difference between acceptable endplay and damaging endplay?

When my revolver (Python) is in full lockup, there is no movement of the cylinder whatsoever, either rotational or lateral (with the trigger held tightly back, its got the "welded to the frame" feel).

When it is not in full lockup there is a touch of roational movement (don't think that's a problem, because the timing seems excellent) and a little lateral movement (endplay). Normally, there's .004" of cylinder gap and in full lockup there's .0015" of gap (reeeeal tight).

So, is the endplay going to cause damage over time by causing the cylinder to slam back and forth between the .0015 position and the .004 posisiton?

Am I totally misunderstanding the mechanics here?

Please, oh folk wise in the way of the wheelgun, enlighten me!!!


Michael.

 

[unspellable]

First, you are not measuring the endplay in the correct manner. With the revolver uncocked push the cylinder all the way to the rear and while holding it there measure the cylinder gap. Then repeat while holding the cylinder all the way forward. The difference in the two measurements is the end play or end shake. That said, you may find it to be 0.0040 - 0.0015 = 0.0025 any way.

I don't now what Colt's specs are for this, but in my own opinion I would say 0.0025 is right at the maximum limit for end play. If it went to 0.0026 I'd start thinking about fixing it. Whether or not I woul fix it at 0.0026 would depend on how easy or how difficult it is to do. For a Smith & WEsson I'd just drop a shim in it. Simple and easy.

Now the rub. I am familiar with the procedures for reducing end play in a Smith & Wesson but not a Colt. The Colt controls end play in a different manner than the Smith. Your cylinder gap is small enough that if you push the cylinder back you will not have excessive cylinder gap.

 

[Michael]

Thanks! I'll check it again tonight.

Much grass, mi amigo....

 

[Michael]

Thanks! I'll check it again tonight.

Much grass, mi amigo....

 

[Michael]

Unspellable -

I measured it both ways, and the gap is .006 when I pull the cylinder all the way to the rear, .003 when I push it all the way to tbe front and .0015 when in full lockup. So, according to your last positing, that makes the endplay .003, which you said was too much.

Does that mean I shouldn't shoot it before I get it taken care of? Could I damage it?

 

[bad shot]

i dont think thats to much cap.it sounds just right .
to tight and it will bind when it heats up and gets dirty,and a 357 mag will get hot.

 

[Michael]

Bad Shot - I'm not concerned about the amount of gap when fired (.0015" in full lockup), rather that the endplay may somehow damage the piece, per Unspellable's comments.

 

[unspellable]

0.0030 inch of end play will not cause immediate damage. How ever, as endplay increases, the rate at which it increases will also increase. The more end play, the more run the cylinder has in which to build up speed before it hits the end, hence more impact and faster wear.

If this were a S&W I'd drop a 0.002 inch shim in the cylinder. Simple fix. But the in the S&W the the bottom of the cylinder well hits the end of the yoke tube and limits forward travel. In a Colt the cylinder neck hits the collar of the yoke and the frame to limit forward travel. And I am not familiar with the methods for correcting this in a Colt. (Don't cry because the S&W is easier to fix, that's also the S&W's weak point, the end of the yoke tube presents a very small surface area to take the pounding.)

before you do anything, check for headspace. You don't want to push the cylinder back and then find you have too little headspace. The tolerances on the headspace are not quite as close as the end shake. You might get some unprimed brass, load the revolver with that and measure the end shake again. This si not really an accurate measurement as brass varies, but is the headspace is on the tight side that may take some of the endshake out.

Now, while I would not like 0.0030 inch of endplay, there are a lot of revolvers out there with that much endplay and owners who are fat, dumb, and happy. How much milage do you put on it? The trade off here is the trouble of fixing it vs. putting up with the accelerated wear which may not be much of an issue if you are not shooting it all that much.

One last point, the reason you don't measure end shake with the revolver cocked is the hand may be pushing the cylinder forward. Since it's spring loaded it really does nothing to actually control the position of the cylinder.

 

[Michael]

Unspellable,

I am impressed with the depth of your understanding and appreciative of your character, which is such that you would take the time to share that knowledge with others.

How is headspace measured, and is the headspace measurement to be simply subtracted from the .003" endplay value?

I thank you again, in advance, for your response.

Michael.

 

[bad shot]

o i understand now

 

[unspellable]

The headspace will vary by the same amount as the cylinder gap when the cylinder moves back and forth.

It's not so simple to measure, as it's hard to get at. It is the distance from the recoil shield in the area around the firing pin (About the size of the cartridge base and centered on the firing pin.) forward to the rear of the cylinder where the cartridge case flange rests against it. In other words it controls how much end play there is in the location of the cartridge itself. In the case of a cylinder with no rebate you might be able to run a feeler gauge through. But as I recall the python has a rebated cylinder so you would probably have to use go/no-go gauges which will look like dummy cartridges with a precisely machined rim. A pair of these will tell you if you are between the minimum and the maximum.

Note that the distance from the recoil shield to the rear of the cylinder in areas away from the firing pin is greater than the headspace to allow free rotation of the cylinder.

That said, head space is rarely a problem. The only time I've seen excessive head space was in a S&W and due to serious yoke end play issues.

 

[Michael]

Again, many thanks Unspellable. Given the endplay in the piece, and my general inability to identify other possible issues with what is, to me, a new firearm, I am going to engage a gunsmith to do an overall tune-up. I'll post another topic now to see if anyone has one to recommend in my region.

Be Well,
Michael.