rings in the cylinder?


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d-dogg
January 24, 2013, 02:11 PM
Would the rings in the cylinder indicate this .357 has fired a boatload of .38 Spl?

Any concerns of firing .357 in it again?

And not to insult the seller if he's a member here, but I'd do a little better job cleaning a gun I was trying to sell. Just saying.....

Thanks,
http://pics.gunbroker.com/GB/326402000/326402868/pix070101607.jpg

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rcmodel
January 24, 2013, 02:30 PM
The dark rings are the ends of the chambers and the step down to the chamber throats.
The other dirt is carbon fouling.

To clean:
1. Get a new .40 cal bronze bore brush.
2. Get a cordless drill.
3. Chuck the brush in the drill and using bore cleaner, spin the brush in each chamber 10-15 seconds while running it in and out.
4. Finish by cleaning with patches & solvent.

rc

The Lone Haranguer
January 24, 2013, 02:30 PM
Even if there are actual carbon rings in there hard enough to prevent a .357 from chambering, they will clean out, IMO.

1911Tuner
January 24, 2013, 02:30 PM
No and no. The "rings" are the chamber shoulders. The short area ahead of the shoulder is known as the chamber throat. Without the shoulders, it would be possible to use .357 Magnum ammunition in a .38 Special revolver.

Clean it and shoot it.

d-dogg
January 24, 2013, 03:27 PM
Maybe it's partly the picture. I just had a look at my .454 Casull, which gets mostly .45 Colt through it, and the chamber shoulders look very well defined in it. (and I noticed a speck in the barrel, so I'm cleaning the whole gun again right now).

The ones in the .357 look worn, but I guess that could be the carbon fouling.

As always, thanks for the info.

9mmepiphany
January 25, 2013, 12:17 AM
Those shoulders look pretty normal to me.

Also, I never expect guns I buy to be cleaned...I'm just going to clean and lube it anyway

hq
January 25, 2013, 09:10 AM
1. Get a new .40 cal bronze bore brush.
2. Get a cordless drill.
3. Chuck the brush in the drill and using bore cleaner, spin the brush in each chamber 10-15 seconds while running it in and out.
4. Finish by cleaning with patches & solvent.

Step 3.5: A Dremel tool, felt tip and the finest jeweler's rouge you can find. Carefully polish the cleaned chambers to a mirror shine.

This reduces the chance of future carbon build-up in the chambers and makes ejecting empty casings easier. This is one of the very few things you actually can use a Dremel tool on guns, without much of a risk of ruining anything.

1911Tuner
January 25, 2013, 01:46 PM
Step 3.5: A Dremel tool, felt tip and the finest jeweler's rouge you can find. Carefully polish the cleaned chambers to a mirror shine.

This is singularly bad advice.

rbernie
January 25, 2013, 01:51 PM
What is the best way to polish tooling marks from a revolver cylinder chamber?

rcmodel
January 25, 2013, 01:51 PM
This is singularly bad advice.
Or Doublearly!! :eek:

If you just gotta do it?
http://www.brownells.com/gunsmith-tools-supplies/handgun-tools/hones-files/handgun-polishing-system-prod649.aspx?ttver=2

But I have very seldon if ever seen a quality revolver that needed any polishing done to any of the chambers.

Please read the "Special Note" here about polishing chambers too smooth!
http://www.brownells.com/userdocs/learn/Inst-450%20Flex%20Hone%20Pol.pdf

rc

murf
January 25, 2013, 01:51 PM
would also clean real good under the ejector star and in the bolt notches.

murf

Jim K
January 25, 2013, 03:03 PM
I keep seeing posts regarding rifle and handgun chambers, with advice to polish chambers to a mirror shine.

That is generally not good advice. When a firearm is fired, the pressure forces the cartridge case walls out against the chamber walls. That reduces the backward pressure on the case and the force applied to the breech face.

But too smooth chamber walls reduce that grip and pressure on the breech face is increased, just like oiling the chamber (another piece of very bad advice.) Manufacturers ensure that chamber walls are polished enough that there will be no extraction problems, but not polished so much that pressure on the breech face will be increased.

Unless there is something seriously wrong with a chamber, put down the emery cloth, crocus cloth, Flitz, etc. Chances are good that that "rough chamber" problem is in your mind, not the firearm.

Jim

303tom
January 25, 2013, 08:44 PM
Try cleaning it once in a while...............

hq
January 26, 2013, 08:40 AM
Please read the "Special Note" here about polishing chambers too smooth!

...which is why I suggested using a rotary tool instead of any abrasive method that changes the direction of microscopic imperfections of the chamber from lateral to longitudinal, which will have a pronounced effect on the cartridge casing 'gripping' the chamber walls under pressure.

If anyone is concerned about a possible increase of load the breech face, it can be gauged piezoelectronically. In my experience, the load increase from factory chambers to a rotary polished one is considerably less than that of a plain worn cylinder, 10-27% compared to a factory new cylinder, the most notable difference being the ease of ejecting spent casings.

Maybe I was wrong suggesting this as a DIY project for anyone who doesn't have means to measure the result accurately; disregard.

Ky Larry
January 26, 2013, 12:57 PM
'Tuner, as usual, nailed it. There are few gun problens that can't be made worse with a Drimmel tool.

Vern Humphrey
January 26, 2013, 01:16 PM
Quote:
Step 3.5: A Dremel tool, felt tip and the finest jeweler's rouge you can find. Carefully polish the cleaned chambers to a mirror shine.

This is singularly bad advice.
Any man who would come within 20 feet of a gun with a Dremel tool ought to be required to take a 10-year time out.:evil:

d-dogg
January 26, 2013, 01:22 PM
Great information here guys.

I have to admit I have always been a cylinder oiler. I see the error of my ways now. Always thought spotlessly clean and well oiled was the way to go.

1911Tuner
January 26, 2013, 06:46 PM
Any man who would come within 20 feet of a gun with a Dremel tool ought to be required to take a 10-year time out.

Testify, brother Humphrey!

Zoogster
January 26, 2013, 07:26 PM
This is singularly bad advice.


Yes it is bad advice. If the gun worked fine before then it will work fine again after being cleaned without removing any steel.

A dremel and rouge is removing steel from the firearm. A bronze brush should not be removing steel from the firearm, but should be removing any carbon and other fouling and buildup over time. That makes a bronze brush superior to fixing the issue with the least wear on the firearm.

Permanently altering the specs of the chambers is just a lazy method of fixing something that only needed to be cleaned.

And of course it makes it easier to eject brass, you just reduced the tolerances of the chamber and made it bigger.

hq
January 27, 2013, 08:44 AM
A dremel and rouge is removing steel from the firearm. A bronze brush should not be removing steel from the firearm, but should be removing any carbon and other fouling and buildup over time. That makes a bronze brush superior to fixing the issue with the least wear on the firearm.

Before theoretical speculation about what actually happens when a mildly abrasive media is applied unidirectionally to existing, machined surface imperfections gets out of hand, I'd recommend taking a very close look at a such surface with a proper microscope as well as gathering data of how this procedure affects breech face load in practice. If gathering first-hand experience isn't practical, there are numerous studies about brass load / primer load on breech face in function of chamber and brass friction coefficient. In practice, reducing the coefficient from 0.25 (rough, 'factory' surface) to 0.1 (attainable without longitudinal application of abrasive media) increases the total load by 15-18%, which is well within specifications even with the hottest loads.

Grinding away enough material to affect chamber dimensions requires some serious effort, but then again, you can never underestimate the extremes some people might go.

Thank you.

Home hobbyists are probably sufficiently discouraged from trying anything like this by now.

Skylerbone
January 27, 2013, 11:22 PM
How does one precisely control and measure for metal removal at 35,000 rpm? I should hope that alone would be enough to discourage anyone from making poor choices.

Alizard
January 28, 2013, 01:56 AM
Any man who would come within 20 feet of a gun with a Dremel tool ought to be required to take a 10-year time out.

I used to say, the first step in any gunsmithing is to put the dremel in the closet and set your bowling ball on it....

As for cleaning the hard carbon burn rings out of a .357 cylinder tube from shooting .38 ammo:

Get a .40 NYLON bore brush and a 6" bore rod. Use a low speed hand drill to spin the bore brush in the tubes. I put a little chrome polish in on the carbon rings with a Q tip then spin away.

If they are really stubborn carbon. Get a scotchbrite pad and cut some narrow strips about 1.5" long. Wrap them into the nylon bore brush and squeeze into the cylinder tubes and spin with drill.

That will get the tubes gleaming clean.

rcmodel
January 28, 2013, 12:13 PM
Scotchbrite pad??

Geeze, it just keeps getting worse & worse.

A Bronze bore brush, solvent, and a cordless drill will take anything out of a chamber the manufacture didn't intend to be in there in about 15 seconds.

With no Scotchbrite abrasives involved.

rc

hq
January 28, 2013, 01:23 PM
At this rate it won't be long until custom gunsmiths will have to look out for angry lynch mobs. Anyone who has replaced his pneumatic die grinder with an electric powered rotary tool will be deemed an infidel and burned on a stake, the only possible redemption being bowing down to the general direction of nearest bronze bore brush factory.

Lighten up, guys. I kind of expected an informed counter-argument about the physics involved in polishing a chamber instead of making an assumption, ignoring everything else and calling a decisively improper technique 'worse' a while later. Worse than what, exactly? Green ultrafine jeweler's rouge, intended for final polishing of soft metals like gold, being even capable of taking a massive bite out of heat treated steel chamber surface in an instant - if at all? :)

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