copper + lead = a crumbly, easy to remove amalgam?

[texassako]

I had never heard of this until reading it in the 2015 Hodgdon's annual I picked up today. It was in an article on one if the new Enduron powders where it talked about reducing copper fouling having been around a long time with artillery using lead sheeting and strands to create an amalgam with the copper in the bore that is easy to remove. If that is so; why do so many scrub out the copper first instead of just shooting some lead bullets and then cleaning? Is the environment in the artillery different enough from our barrels that the amalgam does not form? Is the author misinformed? Mixed up the use of tin to prevent cupro-nickel fouling with lead and copper fouling? I thought it was a curious statement that someone, somewhere, sometime would have discovered and posted here after cleaning a copper fouled bore by simply shooting cast bullets.

[btroj]

Ummmm, I have mentioned this many times?
I find shooting lead over copper fouling helps remove the copper.

http://castboolits.gunloads.com/showthread.php?263046-lead-jacketed-plated-back-and-forth

Take a look at post #2

[texassako]

Ummmm, I have mentioned this many times?
I find shooting lead over copper fouling helps remove the copper.

http://castboolits.gunloads.com/showthread.php?263046-lead-jacketed-plated-back-and-forth

Take a look at post #2

Even in that thread there are several scrub it out posts contrary to your own, and I remember being told here to scrub it out first when I started casting. Scrubbing it out is another often repeated 'fact' I can reconsider as I continue to learn.

[TXGunNut]

It doesn't make sense to me that lead will remove copper but there's plenty about CB's I'm still trying to understand. I make it a practice to remove all (or very nearly all) copper from a bore before shooting CB's in it so I honestly don't know. I'll have to go with btroj on this one, he's obviously had some success with it. Not sure how the amalgam process works but if it works in the big guns and Brad's guns there's obviously something to it.
What the heck is Hodgdon doing coming out with new powders? I generally can't find their current powders in my neck of the woods with any reliability yet.

[btroj]

Ok guys, a couple things I have noticed with this.

Higher velocity and higher Sb alloys seem to do the best job. Antimony wash in the bore seems to help a bunch.

If the copper has a higher affinity for the lead/antimony wash than for the bore the. The copper will come out when you scrub out the antimony wash.

I haven't noticed as much help with handguns as with rifles. Just my observations over the years, never really "tested" anything.

[mold maker]

This is another case where old wives tales and facts get blurred. One article I read, reasoned that the lead covered and stuck to the copper, pulling it loose from the bore. Subsequent lead rounds removed the loosened copper and lead foweling.
Others say the lead builds on the copper, and shrinks the bore making high pressure problems. Still others write that the copper over lead irons the lead into the pores in the bore making removal next to impossible.
I've never tried, or accidentally shot one after the other, and am very interested in this discussion, since most 2nd hand guns have been shot with copper and we mostly shoot lead..

[Duckdog]

If you have the older Lymans Cast Hasndbook, they say to shoot as jacketed bullet asfter shooting lead to clean it out. I have done it and it does work. I can not say that I ever really worried about shooting lead in a barrel that shot copper and it surely doesn ot seem to affect accuracy. In my opinion, it is just a wives tale. In any case, it is very possible that lead also cleans out copper. I do not shoot jacketed very often, so I may never know!

[andrew375]

Yes, very old idea; used a lot in artillery ammunition. Artillery shells ride the lands with copper rings that actually engage the rifling and seal the bore. Inevitably some of the copper gets deposited in the bore causing a change in performance; copper running on steel - good, copper running on copper - bad. To counter this they use a de-coppering shot, which is just a normal round but with a piece of lead foil placed over the propellant. What happens is that the lead and copper forms an inter-metallic compound that, like most inter-metallics, is very hard and brittle and is not stuck to the iron of the bore surface.. The following shot blows out the result, leaving a clean bore.

[runfiverun]

not so much the lead but the antimony dendrites.
if you look in many barrels shot with water dropped ww alloy you will definitely see a grey wash.
that is antimonial wash.
antimony alloys with low amounts of tin will leave a dendrite [little hooks] on the surface and they will scrub a barrel clean, but of course they leave behind that wash.
not an issue, antimony, and lead with antimony actually glides over itself [much the same as a zinc wash works in a cars engine]

[w30wcf]

Ummmm, I have mentioned this many times?
I find shooting lead over copper fouling helps remove the copper.

http://castboolits.gunloads.com/showthread.php?263046-lead-jacketed-plated-back-and-forth

Take a look at post #2

+1 I have had the same experience. I first discovered that several years ago. I had been testing some higher velocity jacketed loads (2,700 f.p.s.) and noted that there was copper wash in the barrel after 20 rounds or so. Time was getting short and I had some cast bullet loads I wanted to test for velocity. I decided to not clean the barrel and fired 10 rounds over the chrono and another 10 for accuracy (they grouped very well).

Alloy was w.w + 2% tin H.T. Velocity of the 205 gr cast bullet was 2,150 f.p.s. When I got home and was getting ready to clean the barrel, I discovered that the copper wash at the muzzle was not there anymore. Thinking that it might be covered up with fouling, I ran a patch with solvent down the barrel followed by a couple of dry patches. There was no leading nor copper fouling.

The copper was indeed gone, obviously cleaned out by the passage of the .002" over groove diameter cast bullets.

I don't shoot a lot of jacketed bullets anymore, but when I do, the cast bullets have done a great job of removing it.

Think about it....copper pipes have been soldered together with tin / lead solder for years and more recently, a tin / antimony mix. In a rifle barrel where there is friction between the cast lead alloy bullet and the copper fouling, it makes perfect sense that the copper fouling would adhere somewhat to the cast bullet with the result that the thin layer of copper fouling would gradually be swept away with the successive passage of each cast bullet.

w30wcf