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Old March 21, 2007, 10:49 PM   #1
bloodtrail
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Lead on outside of cylinder?

Recently shot some .38 special and .357 loads out of my S&W Model 19 and after getting home and cleaning the gun noticed lead on the front end, on the sides of the cylinder just above each chamber. This is on the outside of the cylinder on each of the six chambers, directly on top of each chamber. So when in the firing position looking down the sights from behind the gun, Im talking the twelve o'clock position. Evidently for some reason a small amount of lead seems to be "blowing back" ?? Any ideas? Never noticed this with store bought ammo, and these were the first loads we worked up for the .38 spcl and .357.
Maybe my description is confusing?

Last edited by bloodtrail; March 21, 2007 at 10:50 PM. Reason: wanted to ad more
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Old March 22, 2007, 12:09 AM   #2
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Lead is vaporized from the base of the lead bullets by the burning powder gases, is blown out of the barrel/cylinder gap, is deflected by backwards by the frame and condenses on the face and outside of the cylinder, which is cooler than the gases. You will also often find a little ridge of lead directly above the barrel/cylinder gap.

This is the same way lead gets into the air in indoor ranges.
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Old March 22, 2007, 12:18 PM   #3
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I think it is more gas cut splatter than condensing vapor. May be partly liquid, but I think it's more like a pile of fine spitballs building up. I say that because I put a sight extension on a bull-barrel target pistol that overhangs the muzzle, where gas temperatures are much lower, but it quickly picked up an even thicker cake of lead above the muzzle than my revolvers ever get. Vaporized lead becomes mostly oxide, I expect, and forms part of the white cloud of smoke. Don't want to breath it, whatever form it gets there in.

As to the lead's appearance on the side of the cylinder, it will likely have deflected from the top strap accumulation that Scorch mentioned. I haven't seen it appear at that particular place on my guns. While I doubt it is significant, I would use a feeler gauge to check the barrel/cylinder gap, just to make sure it isn't too wide for best accuracy. Should be in the 0.004"-0.006" range, typically.
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Old March 22, 2007, 03:15 PM   #4
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I have seen the same thing on my revolvers. My M19 gets almost the whole cylinder coated in it between cleanings. It isn't a big deal, it is normal, shoot on.
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Old March 22, 2007, 05:34 PM   #5
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Just curious as to why store bought ammo had never done this, and the first time I shoot some reloads we made(abouts 36-42 rounds worth) I get the lead on the outside of the cylinder near the front edge? Im trying to determine what may be "wrong" or could be done different so that I dont get that? Maybe the loads were "hotter" than the store loads I had been shooting? Although the reloads that we made were under the max loads for the powder/bullets we are using.
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Old March 22, 2007, 05:51 PM   #6
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Just checked the cylinder/barrell gap and it is 0.005"
so that should be ok.
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Old March 22, 2007, 06:30 PM   #7
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Probably nothing wrong with the gun. Lead fouling only happens with lead bullets. Possible reasons:
* Most factory lead loads are very mild.
* Some factory loads use hollow-based bullets to seal the bore in a wide variety of bore diameters, therefore the bullet body is closer to bore diameter.
* Cast bullets are generally resized to .001"-.002" greater than bore diameter to ensure sealing the bore (obturation). That tight fit causes more lead to be pushed off of the bullets, and therefore to wind up on the gun.
* The lead in the factory loads may be harder.
* The factory loads may be jacketed.
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Old March 22, 2007, 08:39 PM   #8
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That's good about the gap. I didn't really expect a problem there, but thought it wouldn't hurt to check, just in case.

I am assuming you are comparing swaged lead commercial loads to cast lead alloy bullet handloads, or you would not be wondering why one causes build-up and not the other? Copper is too hard and has too high a melting point for very much liquid state metal to be produced from it. Your problem is likely a combination of the facts Scorch pointed out and also because the alloy in cast bullets melts at a lower temperature than the alloy in swaged lead bullets. It therefore softens and any melting of particles gas cut from it will occur in greater quantity. Also you may be using a powder charge that is hotter and at higher pressure at the moment the back of the bullet leaps from the chamber to the forcing cone, increasing the velocity of the cutting gas jet that results. Once cut away from the the bullet, lower melting point alloy may become atomized, making it mobile. At that point Scorch's earlier observation about cold metal capturing and freezing it is a likely mechanism.

If you take an old cartridge case and sharpen it with a chamfering tool, you can cut yourself some carboard wads to protect the bullet bases. Soft, low density polyethylene sheet .032" to .063" thick works even better. Give that a try, or buy bullets with gas checks on the bottom to prevent the whole problem from kicking up in the first place.

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Old April 1, 2007, 07:01 PM   #9
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Slugging throats and bore

I would be curious about the size of the throats and bore of said revolver. It could be that you are shooting lead too small for the throats or bore. Nothing like a bullet, .02 or .03 smaller than bore, or throat, letting hot gas dissolve the base of said bullet. Did you slug your throats and bore?
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Old April 1, 2007, 07:12 PM   #10
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No did not slug the bore.........Just bought some 158grain .38spcl/.357 lead from Mastercast and started loading!
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Old April 1, 2007, 09:31 PM   #11
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Good point. If you get Marshall Stantons technical manual at Beartooth Bullets, it has good information on how to measure the groove diameter and throats and also how much bigger the cylinder throats need to be be for standard pressure and for magnum loads, and how to check the fit of your bullets? Cylinder Smith will ream your cylinder for under $40, postage included, if they need it?
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Old April 2, 2007, 03:06 PM   #12
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I have cleaned a few revolvers (two were identical M36's, different owners, others were mixed) that had so much lead the cylinder rotation was not proper. So, no shootum .. which was good. I think it was just a case of hundreds of rounds with cast bullets and inadequate cleaning. After thorough cleaning (kinda a pain!) all functioned well. Get a lead removal set and clean often. There is not a real easy way ... that I have found. Part of the game.

But, do check timing.
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Old April 6, 2007, 06:29 PM   #13
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Fyi

Cast bullets can be found in a variety of hardness. For my pistol shooting, I like hard cast bullets. These are generally harder alloy than what is used for swaged bullets. The old "rule of thumb" is to use your thumbnail. Gouge the base of one of the bullets with your thumbnail. If you get a fairly deep gouge, the bullet is "soft". If you get a very shallow gouge, or just a bright scratch, then the bullet is hard.

Hard cast bullets lead less than soft ones, or swaged bullets. Hard cast are the only lead bullets suitable for heavy/high velocity loadings (unless you enjoy cleaning lead out of your barrel and off of your frame and cylinder).
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Old April 8, 2007, 10:35 PM   #14
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Kleen Bore makes a "Lead Away" cloth that cleans it all up, no problem.
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