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October column: Decoppering Agents #14171282 10/02/19
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DECOPPERING AGENTS

Many rifle powders introduced in the past few years contain decoppering agents, and not just the new IMR Enduron line and the recent Alliant Reloder powder 16, 23 and 26. All Vihtavuori rifle powders now include decoppering, though the announcement seems to have been missed amid the appearances of the newer powders.

[Linked Image]

Why is this happening? One guess might be the increasing popularity of long-range shooting, especially various target games, where a build-up of copper fouling in the bore can affect accuracy.

Then there's high volume varmint shooting, typified by prairie dogs, where several hundred rounds can be expended in one day. For many years the routine among PD shooters was to clean their rifle barrels at least once a day, often in the evening, accompanied by that other essential cleaning solvent, cold beer. This was partly because the job often took a long time, due to a heavy build-up of copper and quite a few cleaning solvents that didn't work all that quickly or well.

Some shooters avoided this by cleaning their bore every 50 rounds or so throughout the day, though often not all that successfully, again because the solvents and routine didn't really remove all the copper, or even most copper. It was more of a feel-good ritual--except for the fact that it often bypassed at 15-30 minutes of PD shooting.

Plenty of Campfire posts still obsess over rifle barrel cleaning, with long threads filled by opinions on the best solvent or cleaning routine. In these threads some shooters adamantly claim they've been using XYZ solvent for decades with perfect satisfaction, while others suggest a combination of 2-3 newer solvents, sometimes mixed together and sometimes applied separately. Then there are arguments over the "proper" bore-brushes and cleaning rods.

It would seem that with l this intense interest in bore-cleaning that many shooters would welcome powders with decoppering agents, yet often somebody expresses skepticism about decoppering powders. This sometimes includes suggesting they may just be another form of "snake oil," an unproven mystery ingredient designed to separate handloaders from their hard-earned money. A little skepticism is healthy for humans, but anybody who thinks decoppering agents are a new fad, or don't work, doesn't know much about the history of smokeless powder and copper.

The first practical smokeless rifle powder was developed in the early 1880s in France, and introduced in the new 8mm Lebel cartridge and bolt-action rifle adopted by the French military in 1886. Soon other countries followed, using variations on the same basic formula. However, all the new smokeless powders resulted in MUCH higher velocities for centerfire rifles than black powder, generally over 2000 fps, which in the next quarter of a century increased to 3000+ fps.

The plain lead bullets normally used with black powder were impractical, due to much of the lead stripping away inside the bore. The solution was a lead core inside a "jacket" of harder metal. The most practical jacket material turned out to be some sort of copper alloy.

However, this did not eliminate bore-fouling, and copper was much harder to remove than lead, especially from military weapons that were fired rapidly and repeatedly, from machine guns to artillery. In large-caliber artillery barrels, strips of copper from the rifling grooves sometimes emerged from the muzzle during a heavy barrage. Obviously this did not help accuracy.

Once again, the French apparently first came up with a solution, discovering that lead wire or foil placed on top of the powder charge vastly reduced or even eliminated copper-fouling. This discovery occurred before World War One, more than a century ago, so no, decoppering agents are not new, or unproven snake oil.

The lead melted from the heat of firing, combining with the copper in the bore, resulting in a brittle alloy that blew out of the barrel during each shot. Or at least that's the primary theory of how decoppering agents function. There may also be some melting of the copper--but the mail point is decoppering agents work, and have for a long time.

However, placing chunks of lead over the powder charge wasn't very practical with ammo fired in smaller rifles. Instead powder companies eventually started including particles of decoppering agents in the granules. Tin proved to have the same effect as lead, and by the 1920's some DuPont rifles powders included tin, denoted by "1/2" after the powder's name. Gun writers of the era sometimes noted that the tin often fouled the bores worse than copper jackets.
However, eventually both tin and bismuth proved to be the most practical decoppering agents, especially after lead became widely considered an environmental poison. (The problem with the early DuPont 1/2 powders wasn't the tin itself, but too much tin in the powder, resulting in the tin fouling.)

Decoppering agents were used in quite a few military powders by World War Two, especially the Ball powders developed by Olin in the 1930's. Ball powders were not only cheaper to make than extruded powders (in fact they could be made from recycled extruded powders) but speeded up production of military ammunition, since they flowed easily and accurately through mechanized powder measures.

Unfortunately, early Ball powders (or spherical powders, as they're generically called, since "Ball" was a trademarked by Olin) also left a lot of residue inside bores, due to the burn-resistant coatings that made slower-burning spherical powders possible. This fouling was relatively abrasive, so tended to rub more copper from bullet jackets, at least somewhat counteracting the decoppering agents.

Many recent powders, both spherical and extruded, tend to burn far cleaner, leaving far less abrasive powder fouling in the bore. As a result, decoppering agents are more effective. Today they're usually bismuth or a tin-bismuth combination, and work very well.

However, one problem that can still compromise their effectiveness is the ratio of decoppering agent to powder. Rifle cartridges vary considerably in their powder capacity to bore ratio, and bullets also vary considerably in how much they contact the bore. Then there's the jacket itself (or these days, the entire bullet), which can be anything from pure copper to pretty hard brass. As a result, while decoppering agents always reduce copper fouling, they may not totally eliminate it in some cartridge/bullet combinations.

[Linked Image]
Despite pretty long boattails, many of today's high-BC bullets have more contact with the bore, due to often being heavier in weight.

Plus, some barrels copper-foul more than others. I've owned factory rifles with barrels that became about copper-plated within 20 rounds, and other barrels (usually hand-lapped customs) that almost refused to copper-foul. Of course, there are also bore treatments to reduce copper fouling. Since around 2007, many shooters have used Dyna-Tek Bore Coat to fix (or at least tame) rifle barrels that tend to copper-foul.

But using powders with decoppering agents can work at least as well these days, partly because factory barrels have become smoother, even in some very inexpensive rifles. My most recent example is a new Mauser Model 18 in 7mm Remington Magnum, sent to me for magazine reviewing. The 18 is a sort of Euro-version of inexpensive American rifles, real-world retailing for around $500, though the injection-molded stock and easily adjustable trigger are superior to many other "affordable" rifles. Like other recent Mausers I've tested, the hammer-forged bore proved to be very smooth in my Gradient Lens Hawkeye Bore-Scope.

[Linked Image]

The Model 18 was fired 10 times during its first range-test, using inexpensive factory ammo to get zeroed, and check magazine feeding and other functions. Back home the Hawkeye revealed some copper fouling in the corners of the lands, but probably not enough to affect accuracy, so I didn't bother cleaning the barrel.

I then fired 90 more rounds during three range sessions without cleaning the bore, while trying various new bullets and powders. Three of the powders did not contain decoppering agents, so I alternated those rounds with others loaded with decoppering powders. In total, 14 of the 90 rounds were non-decoppering.

After a total of 105 rounds I used rubbing alcohol to remove the minimal amount of powder fouling from the barrel, then again checked the bore with the Hawkeye. The trace of copper fouling visible after the first 15 rounds was gone, despite around 20% of the rounds fired using non-decoppering powder. Essentially, it was a clean barrel.

I have seen the same sort of thing in several other new factory rifles during recent tests, including Franchi Momentums, Ruger Americans and Sauer 100s and 101s, all of which, like the new Mausers, also feature very smooth hammer-forged barrels. Much of the testing involved newer bullets with very high ballistic coefficients, which despite having long boattails still have plenty of contact with the bore due to their relatively heavy weights.

So do decoppering agents work? Yes, they do, but exactly how well they work in a particular barrels depends on several factors--and a bore-scope is pretty much essential in determining the outcome. You really cannot tell if a rifle's bore is cleaned of all copper by relying on anything else: I have used mine to examine many barrels that in theory should have been perfectly clean, due to a lack of "blue" on cotton patches used with ammonia-based solvents, and still found some copper, often quite a bit. The same has been true of any other cleaning product, whether abrasive, a "lifter," or another kind of copper solvent.

The other question, of course, is how much copper fouling reduces accuracy. Sometimes a moderate amount doesn't seem to hurt, but I have yet to encounter a rifle that really shot well with considerable copper in its bore. This is one reason I started keeping an accurate round-count, including cleaning intervals, on all my rifles many years ago. But in general most rifles, whether factory or custom, do shoot better when unfouled.

I've now had a Hawkeye for over 15 years, the last 2-3 with the latest model with upgraded optics. They're pretty expensive, but when I first purchased mine they were pretty much the only option--and contrary to what many shooters believe, they will not tell you much about whether a barrel will shoot well. Instead a scope is far more valuable in determining how well various cleaning products work, how well a chamber is cut, how much throat erosion is taking place, or how many "fire-lapping" bullets are required to smooth up a rough throat.

[Linked Image]

Today, however, there are far less expensive digital bore-scopes on the market. So far I haven't tried any that reveal the same level of detail as the Hawkeye, but any will show basic copper fouling.

What I do know is that anybody who dislikes spending time cleaning barrels, instead of shooting, will benefit from decoppering powders. That's exactly why I started experimenting with various techniques that reduce copper fouling many years ago, and why many of the rifle powders I use these days include decoppering agents. Most also tend to be temperature-resistant powders, which also helps in consistent results.

You may not "need" either for the shooting you do (and I certainly don't in some of my rifles, such as my traditional, iron-sighted lever-actions) but with so many 21st-century rifle powders featuring decoppering agents, its pretty easy to find one that works very well in any of today's super-accurate bolt actions, whether factory or custom.

The Mauser 18 shot VERY well with several loads using bullets from 120 to 195 grains, and by very well I do not mean MOA but much better. Which is one reason it's no longer one of the "loaner" test-rifles that regularly reside in one corner of my safe, but belongs to me.


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John Steinbeck
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Re: October column: Decoppering Agents [Re: Mule Deer] #14171364 10/02/19
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I can’t wait to read the article. I enjoy your writing very much. I’ve been an IMR 4350 man for 40 years. I’ve had such good luck with it in 25-06 to 7 Rem mags. I’ve had a hard time convincing myself to put down the IMR 4350. Which powder would you recommend to replace it? Thank you!

Re: October column: Decoppering Agents [Re: Mule Deer] #14171426 10/02/19
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I bet he'll say IMR4451, given the 4350 burn rate and decoppering being the present context.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
Re: October column: Decoppering Agents [Re: Mule Deer] #14171506 10/02/19
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That would be correct

Except that IMR4350 reasonably temp-resistant, certainly enough for hunting in Texas, and unless copper-fouling is a problem there's no real reason to change.


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
Re: October column: Decoppering Agents [Re: Mule Deer] #14171512 10/02/19
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4451 is a bit easier through a powder measure.


"In the real world, think of the 6.5 Creedmoor as the modernized/standardized/optimized version of the 6.5x55/.260." John Barsness 2019
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Re: October column: Decoppering Agents [Re: Mule Deer] #14171598 10/02/19
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I field about 10 new guns a season.
I have about 60 different powders.

The only powders I will used this year are CFE 223 and IMR-4166.
Last year I also used IMR-4451.

I coat the bore with Bore Cote.
I coat the bullets with moly.

I never shoot bullets over 3600 fps.

I hate Copper fouling.

I take Witch's Brew, Kroil, KG-12, KG-1, Alcohol, and lots of Bronze brushes with me on a 3 week hunting trip.


There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. -Ernest Hemingway
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Re: October column: Decoppering Agents [Re: Mule Deer] #14171814 10/02/19
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Good article. Bore Coat and de-coppering powder and I can almost throw away all my cleaning supplies. This brings up the question of why bullet coatings are not more successful? They certainly work on cast bullets. I was a fan of the Barnes blue pills. Moly is such a pain to get out of the barrel to me it is worse than copper. I haven't tried dansak. I am curious if Dyna Tek would work on bullets?


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Re: October column: Decoppering Agents [Re: Clarkm] #14172658 10/02/19
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Clark,

You may even be more OCD than me....


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
Re: October column: Decoppering Agents [Re: Mule Deer] #14172754 10/02/19
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John, how do you think this would affect the accuracy of those rifles that appear to shoot better with a slightly fouled barrel?


"You may all go to Hell, and I will go to Texas" - Davy Crockett
Re: October column: Decoppering Agents [Re: Mule Deer] #14173144 10/02/19
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Dunno until you test 'em.

One other thing many shooters obsess about is powder fouling, which they often clean obsessively whenever they get rid of copper. But Dan Lilja believes some powder fouling helps accuracy, and makes a good case for it on his website, based on considerable testing.


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Re: October column: Decoppering Agents [Re: Mule Deer] #14311445 11/25/19
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Is there a list, out there somewhere, of contemporary commercially available powders from all manufacturers that include decoppering agents in their constitution? I am currently having trouble finding any N133 locally in Northern Colorado, and would like to know if there is a very similar powder out there that includes a decoppering agent. If Benchmark had a decoppering agent, I would be golden, but it doesn’t. I hate having to order powder, especially if it’s a pound of powder that I’d like to just try out.

Re: October column: Decoppering Agents [Re: ColoradoMatt] #14311841 11/25/19
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Matt,

The list changes all the time these days--and burn rate is also dependent on specific cartridge/bullet application. What are you loading?

Without that specific info, would probably suggest CFE223.


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
Re: October column: Decoppering Agents [Re: Mule Deer] #14312737 11/26/19
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Originally Posted by Mule Deer
Matt,

The list changes all the time these days--and burn rate is also dependent on specific cartridge/bullet application. What are you loading?

Without that specific info, would probably suggest CFE223.


I was thinking CFE223 is too slow for my application. I picked up a like new M70 classic compact in 308, and I would like to load 110 grain Nosler Varmageddons for coyotes. The Nosler Manuel indicates best accuracy with Benchmark, and N133 seems very similar, but I’d like to make the low copper switch with all my reloading, where practical. I’ve been using 24 grains of Benchmark and 50 grain BT’s in the 222 ever since Benmark came out 20 years ago. There are better options for coyote hunting, I know, but I like the reloading challenge, and any excuse to take the cute little rifle in the field. BTW, I’ve wanted a classic compact ever since you wrote about one in 7mm-08 in Rifle Magazine years ago. Come to think of it, you planted the seeds love in my heart for the 257 Roberts and 7x57 with respective articles in “Hunting Horizons” magazines when I was in college. Thank you! I am a shameless Acolyte.

Last edited by ColoradoMatt; 11/26/19.
Re: October column: Decoppering Agents [Re: ColoradoMatt] #14312783 11/26/19
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Wow, good to know I have an acolyte! Thanks.

You're probably right about CFE223. Hodgdon lists data with 150-grain bullets but not 110s.

You might try IMR4166. While Hodgdon does not list it with 110s, it does list both H4895 and IMR4895. In my experience (which includes analyzing Hodgdon's data) 4166 is very similar in burn-rate to those two powders.


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
Re: October column: Decoppering Agents [Re: Mule Deer] #14312855 11/26/19
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Thanks, John. I’ll give 4166 a try.

Re: October column: Decoppering Agents [Re: Mule Deer] #14386953 12/19/19
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Mule dear.
I assume you are JB, after reading big book of gun hack I managed to get hold of some cfe223, I use it exclusively in my sons 308, my 35 Whelan and a 222 rem 788.
I used to clean all these after every range session. After using cfe223 I only cleanwhen accuracy starts to decline.
I don't know when that will determine as all still shoot .3-.75 moa and all have had in excess of 150 rounds up the spout.
Good stuff that cfe223. If you want something to give a 35 Whelan a set of gonads try it.
Speer list the 250 grain hotcore at almost 2,700fps. I can verify this ,I used their load of 64grain cfe223 and got 2,750fps out of my rebarreled Stevens 200 with easy extraction, rounder primers and minimal CHE.
LOAD FROM A DISC lists loads for a lot of calibers with this powder. Use it and enjoy minimal cleaning, just oil put it away and swab the oil out with a patch and keep shooting.

My big regret is that they don't import it into OZ any more, lucky enough to to have a stock of 20 bottles of the stuff hoarded.


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