THOUGHTS ON BORE FOULING AND CLEANING

Whether we shoot copper jacketed, solid copper or lead bullets that are a few basic facts that are always applicable.
ØAll barrels foul. Regardless if the barrel is manufactured by the hammer forged, broached or button rifled process all barrels will and do foul. Custom made, air gauged, hand lapped barrels are no exception. No matter how a barrel is manufactured there will be microscopic holes in the crystalline structure of the steel. Copper and/or lead will collect in these voids.
ØThe longer the barrel and the faster the rifling twist the more a barrel will tend to foul.
ØChrome molly 4140 – 4142 foul more than 416 stainless.
ØAll types of fouling is not bad. In fact some is good.

There are at least four areas of a bore where fouling can occur.
ØIt is most noticeable in the throat or forcing cone area. Copper or lead fouling in this area is often seen as a lumpy build up that will quickly worsen negatively affecting accuracy.
ØA second area that is readily seen is in inclusion and pit areas of poorly manufactured hammer forged and/or severely corroded barrels.
ØThe third area is on the lands and grooves and is seen as a copper or lead streaking. This is the area that is usually discussed when reference is made to shooting a copper jacketed bullet to clean out the leading.
ØThe forth area of potential fouling is in shallow reamer marks and scratches. Copper and leading in these areas are generally difficult to see without the use of a bore scope and are of no significant import relatively to accuracy provided that the fouling is not allowed to build up. When build-up becomes severe bumps of lead or copper above the bore surface create restrictions that tear the bullet ogive and base as it passes down the length of the barrel. This deforms the bullet and negatively effects consistent bullet flight.

Remember, all barrels foul. It is a simple matter of how many shots are needed to first stabilize velocity then how quickly it fouls so severely that the barrel starts to toss flyers or errant shots. If it takes nearly 10 shots for velocities to stabilize and at that point the barrel is fouled so severely accuracy is impossible you have a problem. The barrel is called a “fouler.” New commercial barrels may foul very badly after only 10 shots. Even new custom made barrels may foul badly after 20 or so. Both can be improved.

“Shooting In the Barrel.” This is how it works – First the barrel needs to be cleaned completely of all copper or lead down to the bare steel. Next shoot a copper jacketed round followed by cleaning with a wet patch of a powder solvent such as Hoppes No.9 to remove the powder residue followed by a dry patch or two so you are down to copper. Next wet patch with an ammonia base copper solvent. Wait a few minutes repeating the step until no copper residue comes out on the patch (usually a blue or green in color). Repeat this process until a single shot produces no copper residue on the first patch. Then go to two shots at a time, then three, etc. The goal is to be able to shoot 10 shots before you get copper deposits from the bore. Once accomplished this should allow at least 15 or more shots before there is sufficient fouling to toss flyers and velocities should stabilize quicker from a cold barrel. This is a time consuming procedure for rifles, much less time consuming for handguns, but the effort will be well worth it. Eventually the barrel will clean with just a few patches and no scrubbing with brushes will be required. It is important to break-in a barrel. The major portion of jacket material or lead must be removed by each successive shot or it will pick-up more fouling and build on itself. It is important, therefore, to get a layer of carbon fouling on the top of the lands and grooves as this hard deposit will prevent copper or lead from stripping from the bullet. This is the good fouling. Why does the break in process work? As already stated there are microscopic holes in the crystalline structure of the steel. Copper and lead collect in the voids. Because like materials tend to attach to one another more and more accumulates until fouling material is higher than the bore surface. This is when accuracy will severely deteriorate and you feel the roughness when a tight patch is pushed through the bore. Copper solvent removes the copper from the voids so each successive shot can slough surface molecules into and over the voids until they are nearly closed. The result is a smoother bore and much less fouling. Note: never use a stainless brush as they do damage the bore. If you find it necessary to use a bronze brush push it entirely through the barrel in one complete motion. Do not pump the brush back and forth. Always use a bore guide for rifles and a muzzle guard for handguns to prevent uneven wear of the rifling forward of the chamber or the crown. Top shooters never pull a metal brush backward through the bore and only use nylon brushes and patches to remove powder fouling. If the barrel is good you should never need to clean it with a metal brush. Obviously if you have a barrel with severe rough spots or tool marks then those areas will not smooth out with the aforementioned procedure. Some advocate that lapping with very fine lapping compound or shooting abrasive jacketed bullets through a thoroughly cleaned bore. I am not a proponent of these methods for various reasons. As it relates to cleaning rods, forget aluminum and uncoated steel. Fouling and dirt attach easily to the surface of aluminum and cause scratches. Spring steel rods can wear on the edges of the lands. Brass, coated steel and carbon fiber are the materials of choice. You should be able to purchase one good rod for handguns and one good rod for riles under .30 caliber and another for .30 caliber plus. With these rods you should be able to attach all loops, jags and brushes with the proper fittings for any caliber guns that you may have.

Can your barrel be too clean? You’re kidding me – right? Nope, if a shooter uses an abrasive type cleaner too often the abrasives can be very effective at removing all traces of powder, carbon and jacket or lead fouling. The abrasives can get the barrel too clean. In effect the shooter is re-breaking in the barrel every time he cleans. This ends up in the dog chasing its tail scenario where the shooter believes his barrel is a fouler because of copper or lead accumulation in the barrel is always present so he works to remove it with more abrasive cleaner but what he does remove is the desirable layer of carbon fouling left by the powder and exposes the bare steel ready to grab lead or copper with the next shot.

Copper fouling – It takes several shots to first heat and then foul a cold clean barrel so velocities stabilize and optimum accuracy is reached. This is because initial shots through a cold clean barrel produce different frictional energy until lube is blown out or laid down and the bore is coated with carbon residue, bullet lube or copper so the bullet friction begins to stabilize. Copper fouling grows! Soft metals gall and stick to similar metal. Each round fired will deposit a little more until accuracy deteriorates. Once a barrel is copper fouled successive shots will not remove the copper. Copper is not easily removed by scrubbing but it is easily removed with a good copper solvent. Ammonia has been the chemical of choice from removing copper from barrels for over 100 years. I have never seen detrimental affects from using an ammonia based cleaner if it is thoroughly removed from the barrel as per the manufacturer’s directions. Here is a link to some excellent test results relative to copper removing solutions Gun Cleaning Product Tests If you watch a bench rest shooter you will notice that although he or she is probably using a custom high grade barrel he or she does not fire many shots between cleanings as compared to the string of shots most casual shooters fire through their handguns or rifles. This is because accomplished shooters understand that the copper fouling needs to be removed before severe build up happens. They also understand that it is detrimental to remove the protective layer of carbon fouling.

Lead bullets and fouling – The successful use of non jacketed lead bullets involves several factors that are not of normal concern when using jacketed or solid copper bullets. By “successful use” I mean keeping fouling to a minimum and accuracy to an optimum. Recently shooters of lead bullets seem obsessed with the BHN (Brinell Hardness Number) of the lead bullets that they buy or cast. They believe that if they know the hardness of the bullet they can correctly select the right bullet for their particular application. I don’t strictly rely on BHN numbers when selecting bullets because it is only one measured aspect of a cast alloy. Some bullet companies offer published pressure equations that supposedly allow a shooter to determine the amount of hardness needed for a particular load at a known velocity. These equations supposedly show how much pressure is required to make the bullet expand (obdurate) in order for the bullet to fill the lands and grooves. This was important back in the old days of black powder when barrel dimensions varied greatly from one maker to another and even with the same maker. In modern times tolerances have been some- what consistent through the generations of handguns with most of the variation being seen in the cylinder throats. Once you know that dimension for your particular gun then bullet selection for the proper fit is easy. Once you get bullets of a proper fit then obduration no longer becomes necessary to get an effective seal. If the bullet is at or over the largest throat dimension then the bullet will swage down and seal with a perfect fit. The only time this becomes a problem is if the throat dimensions are off by a large margin of more than .002-.003 over the bore dimension. A differential above .003 can cause the bullet to strip within the barrel leaving long stings of leading the length of the barrel.

BHN –vs- Alloy Strength – BHN tells only how hard something is. It tells nothing about alloy strength. You can compare two bullets with the same BHN and one will be more brittle with a higher content of antimony in its composition and very prone to lead fouling while the other will be much stronger, far more ductile and less prone to leading the bore. The standard 2/6 alloy (2% tin, 6% antimony, 92% lead) was not developed for its performance as a cast bullet alloy but because it would pour and run well in automated casting machines. Linotype a 4/12 alloy (4% tin, 12% antimony, 84% lead) is a eutectic alloy meaning that all of the components will melt at the same temperature. In its alloy form it was (I say “was” because it is now almost non existent in the US) too hard for cast bullets except for rifles shooting velocities of 2100 fps. Another alloy is Lyman #2 which is a 5/5 alloy (5% tin, 5% antimony, 90% lead). It is expensive to produce in large quantities and thus expensive to buy. The 1 to 1 ratio produced an alloy that did have a high BHN but is almost as strong as linotype.

The advantages of shooting lead –vs- copper jacketed or solid copper bullets is that most copper bullets run about 35 BHN compared to 21-22 BHN of lead bullets, copper is more abrasive, more difficult to remove and offers no lubrication. Lead is less abrasive than copper by 10 to 1.

Lead fouling - The biggest concern voiced by shooters who are contemplating using lead bullets is the amount of lead fouling that they will have to contend with. Lead fouling is proportionate to the barrel condition, use of proper sized bullets and proper powder. Lead fouling is easier to remove than copper and when correctly loaded with proper size bullets and lube there may be almost no residual lead fouling to clean after shooting hundreds of rounds. Just forward of the throat or forcing cone area, breach bore fouling is found in the 1st ½” or so of the barrel. There is much speculation as to the cause including: constriction of the forcing cone area when the barrel was threaded and crush fitted into the frame, gas cutting causing melted bullet base material, bullets that are too hard or bullets that are too soft. When the bullet first engages the rifling at which point the bullet engraves, the lands act as a cutter that cut through the lead or copper surface. Since the bullet is not ductile it will tend to foul more in this area. Some casters try to overcome this problem with additional lubrication. Many lubes used by bullet makers were selected for their ease of application in the bullet making process rather than their lubrication qualities. A medium hard lube will provide the best lubrication from breech to bore ends of the barrel. Breech bore fouling is most affected and cured by finding the proper powder speed for the particular load. Revolver and pistol shooters used to be limited to just a few powder selections most that were hot and fast and not well suited to lead bullet use. This may well be why Elmer Keith chose 2400 for several of his pet loads. Currently we have many powder choices that offer cooler burning temperatures, better pressure curves and improved cleanliness of powder residue. Barrel fouling in the form of long streaks of lead the length of the barrel from breech to muzzle generally indicate improper bullet fit and improper alloy. Fouling at or near the muzzle end indicates too much velocity or lube that is not performing with the velocity. Following the basic rule that as velocity goes up move down in powder speed often provides a cure. Slower burning powders like Allient 2400, Accurate Arms #9, Winchester WW296, Hodgdon H110 and Little Gun and IMR 4227 seem to work well to achieve magnum velocity without lead fouling. There are several lead remover solutions that work well and the Lewis Lead Remover tool for removing excessive lead build-up. The key with leading as with copper fouling is to keep the fouling to a minimum which will minimize your cleaning efforts.

The subject of barrel break-in, bore fouling, barrel cleaning and lead bullet fitting are controversial subjects upon which even the most learned ballisticians and writers often disagree. The above simply represents my experiences and thoughts on those issues.

To help visualize various bore conditions and what certain fouling looks like, below are several 20X magnified bore photos that were provided as a courtesy from Ken Harrington of the Gradient Lens Corp.


Surface rust


Severe pits in neglected barrel


Pitting in poorly made hammer forged barrel


Fire cracking in leade area


Leading in Throat area


Copper fouling in groove & on edge of land


Copper fouling and damage from steel cleaning rod


Lead fouling on land. Note discoloration of lead from powder residue. No copper present

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Doug

Doug, many thanks. That may be the most comprehensive, realistic, and accurate, treatise I have read on this subject. In my opinion, it is more than most advanced shooters and reloaders will easily absorb at first reading. But that also means it will likely meet the needs of the most technically inclined perfectionist. Your thoughts obviously reflect years of study and analysis. Good work, and the photos add a lot.

Outstanding explanation. Great info. this should be posted on all the reloading forums. Thanks for the write up.

Doug,

That was a very nice and educational commentary! I actually read it twice to make sure I absorbed the information you posted.

Now I have a question for you that has perplexed me for some time. I own a few WWll Military rifles such as an M1 Garand and M1 Carbine that shoot copper jacketed ammo only. In the instructional booklet that came with the Carbine it specifically states NOT to use copper bore cleaner because it will migrate into the hole in the barrel and screw up the piston. They also advise NOT removing the piston for cleaning on a regular basis, as it is staked. I have a can of the foam type copper cleaner as well, and again they state that it should not be used on gas operated weapons for the same reason. I have been using a standard cleaning solution and while it does clean the barrel after a fashion, I know there is still copper fowling in it.

I would appreciate your thoughts on this matter, and I thank you in advance.

Regards,
chief38

Firearmsunlimited:

By the way Doug, I read some of your "there ought to be a law" - GREAT!!
Will read the rest when I get a spare moment.

chief38

Hi Chief,

I am not an expert on Garands or carbines but here is my limited understanding.

Based on the assumption that both are CMP guns. The carbine has a floating piston held by an insert at the bottom of the lug area that is staked in place. It requires a special spanner wrench for removal. There are no copper or brass pieces that comprise the piston assembly. With that said, clearly they just do not want someone to get any kind of non lubricating solution into the piston area as it could prevent cycling either through corrosion or hydraulic effect. Therefore, if you really feel the need to attempt copper fouling removal I would relegate my efforts to using JB Bore Past. There is a trick to using it that can be found on Brownell's web site under articles - bench rest shooting. Concerning the Garand the piston is attached to the operating rod and is easily disassembled. You should be able to disassemble it and use any cleaner, as again there are no copper or brass parts. There is a general precaution concerning Garands that indicates that it should be cleaned up-side-down meaning if you have it in a gun cleaning cradle you want the sights facing down toward the floor. I believe the reason for this is that you do not want to get fluid in the gas port which is just a drilled hole on the top of the barrel. As you probably already know, collector Garands are bought and sold based upon the amount of wear in the muzzle end of the barrel and the chamber throat. The muzzle wear clearly came from the use of steel cleaning rods during military use. My point here is two fold, first if your muzzle shows .04 - .06 wear the rifle will probably never be an excellent shooter. If it has a good muzzle measurement (.03 or less) be sure to use a good cleaning rod to prevent future wear. Hope this helps.

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Doug

Thanks Doug. I am familiar with the disassemble of the gas piston on the Garand and have removed it for cleaning a few times. As far a the Carbine is concerned, I guess I will just use conventional bore cleaner and a bronze brush. The strange part is that the instructions that came with the Carbine say to clean it upside down to avoid getting cleaning fluid into the hole in the barrel, but when you are done cleaning it, turn the rifle right side up and pass an oily patch through it so a bit of oil gets into it. I would think a combination of oil & carbon would gunk up the piston, but that is what they say to do.

I am going to check out the Brownell's web site in a minute as per your suggestion. Thank you.

Regards,
chief38

Great info. I'm going to print out a copy for future reference.

I'm constantly amazed by the amount of knowledge freely shared on internet forums. Thank you.

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Andy

An important point to remember is that if you use an aluminum cleaning rod, with aluminum/brass/synthetic tips, you eliminate the risk of grinding up any part of the bore with steel cleaning tools.

Personally I shy away from the aluminum rods because grit and grime can easily attach to the aluminum. If your patches are at the correct tightness when patching the barrel the rod will bow and a portion will come into contact with the lands. Also, an aluminum rod does have a propensity to bend which will set unlike the springy steel or carbon fiber. A coated steel (Dewey) or a carbon fiber (Tipton) IMHO a far better choice.

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Doug

Great information OP. Thanks for sharing.

Cheers,


Geoff

I would recommend that those of you that are interested in collecting or using the M1 Carbine and M1 Garand visit Scott Duff's Website: Scott Duff Publications & Historic Martial Arms: M1 Garand, M1 Carbine, M1903, Krag, M1911A1. Scott Duff is one of the recognized experts on the M1 Garand and M1 Carbine. He has owner's guides on both weapons. Additionally, he sells Dewey cleaning rods and rod guides. I am not affiliated with Mr. Duff, but have benefitted from his knowledge and expertise.

Thanks for a great thread and especially for addressing a currently popular myth, that is, matching cast bullet hardness to velocity. This notion is bogus and, as you alluded, the determining factor in preventing leading is correct sizing & lubrication of the cast bullet. Stating that a cast bullet is "too hard" and will therefore invariably lead the bore is absolutely false.



Bruce

Thanks Doug, great article!

Doug, you make some good points regarding cautions with the use of softer and less strong aluminum rods. I still like them but, as you note, they can bend, possibly hold abrasives, and you dare not fit patches as tightly. Coated steel might be ideal. I have not tried the carbon fiber rods.

The last couple years, I've had to reexamine my earlier assumptions regarding bullet hardness and permissible velocities to avoid leading. What has happened is that modern synthetic bullet lubricants, especially those containing what is commonly referred to as "Alox", have evolved to the point where they, combined with other things, plus the use of gas checks, can just about eliminate leading with cast bullets.

Indeed, perfect alloy and hardness are not nearly as important as in bygone years, if bullets are correctly sized to the bore. It was with considerable misgiving that I tried switching to straight wheel weight alloy (although "alloy" is pretty broad) for speeds in the 1000 to 1400 FPS range a few years ago. And that was without Alox; just one pound parafin, one pound Vaseline, and a big tablespoon of RCBS case lube. No leading. Then I dropped the case lube for the dirt cheap automotive STP, just to see if it would work as well. It did. I got away with eliminating the nearly unobtainable tin for 9mm speeds in the 1100-nearly 1400 FPS range. Same in .32-20 rifle loads, without gas checks. It worked.

I got brave and tried all this with M-1 carbine cast gas check bullet loads at about 1800 FPS. Same result; no problem and especially, no lead transfer into the gas cylinder/piston area. That amazed me.

I was sure this would not apply also to the M-1 Garand and its gas system. I was wrong again. Decades earlier, I had leaded one up badly. Not true this time, a few years ago. Maybe today's wheel weights, decent bullet lube, and gas checks just prevent it better than whatever I used in the '60s.

Then came experiments with 8 x 57mm and .308W gas check cast loads in the 2100 - 2400 FPS range also. I was sure I would get at least some leading there. I didn't. My previous beliefs and assumptions took a big hit again, and reloading costs happily dropped.

I think the lesson I have learned is, "Try it, before accepting popular howls that it won't work." And be willing to experiment, within the constraints of basic reloading safety rules.

Since my current lube recipe works (slight variation on an old NRA recipe), I'll use it up before moving to my next experimental batch, which will contain a lot of beeswax and several types of "Alox" type lubes which I have been stockpiling.

Part of the satisfaction of reloading is not stopping with that which works well. It's fun to explore other things which also work, maybe even better.

Right now, I've been enjoying threads on this site regarding home formed gas checks. I am almost ready to accept that even aluminum gas checks are practical, at rifle velocities. I'm still cautious about that, for the same reasons Doug doesn't like aluminum cleaning rods. But I may be wrong again, as a number of people posting on this website are using them successfully. The cost savings would be quite a breakthrough.

One challenge I may never be able to overcome is figuring out why so many of the local shooters I know are steadfast in refusing to even try cast lead bullets, their own or commercial ones, for either handgun or rifle loads. But I guess that helps hold down the number of us who are beating the bushes for scrap wheel weights, while we can still get them for $.10/lb., as I did last Friday. I think my lady friend has questions about the mental processes generating my great joy over the acquisition of a 100 pound plastic pail full of filthy old pieces of something-or-other from the tire shop for $10. I'll bet the other patients here would be much more understanding.

<Personally I shy away from the aluminum rods because grit and grime can easily attach to the aluminum. If your patches are at the correct tightness when patching the barrel the rod will bow and a portion will come into contact with the lands. Also, an aluminum rod does have a propensity to bend which will set unlike the springy steel or carbon fiber. A coated steel (Dewey) or a carbon fiber (Tipton) IMHO a far better choice.>

One would think that the nylon coating of a Dewey rod would more easily imbed grit and grime than any other rod. The fact of the matter is that most folks wipe their rods and use a bore guide. The folks at Pro-Shot that make those highly polished stainless steel rods may take issue with a claim that their rods will harm your bore. I have both Dewey and Pro-Shot rods. Both are perfectly satisfactory. That said, I wipe them clean and use a bore guide, before they ever enter the bore. I have misgivings about these carbon fiber rods and here's why:

I have spent countless hours poling a skiff fishing for bonefish, tarpon, and such in south Florida. I have used graphite composite/carbon fiber push-poles, as well as various blends of E and S fiberglass poles. The carbon fiber poles, while light and stiff, seem to deteriorate more quickly in an outdoor marine environment. The carbon fiber has a tendency to slough off in time. How do I know this? These fibers become embedded in the skin of my wrists and forearm, as I routinely pole the boat. The itch at the end of the day tells the story. I've learned to wear a long sleeve shirt for sun protection, as well as itch proofing. Granted the marine environment is probably a bit harsher, but I really don't know how all the various bore cleaning concoctions react with these carbon fiber rods. I personally do not want anything coming off a cleaning rod and getting shoved back and forth in my bore. I suspect that the carbon fiber rods are more of a marketing gimmick than anything. Carbon fiber is "high tech"............Highly polished, hard stainless steel is pretty inert. If the Pro-Shot rods give you pause, use a coated Dewey.

<Once you get bullets of a proper fit then obduration no longer becomes necessary to get an effective seal. If the bullet is at or over the largest throat dimension then the bullet will swage down and seal with a perfect fit.>

This is not true, given the context of your remarks concerning barrel leading. A bullet that is too hard for a low pressure/low velocity round will not "swage" down and seal the bore.........even with a proper fit. If that was true, all bullets could be cast slightly oversized and as hard as you cared to cast them. On the flip side, perfectly fit soft lead bullets will lead like crazy if driven to excessive pressures and velocities. A perfect example of this is a 148gr. HBWC for bullseye shooting in the 38 Special. That hollow base wadcutter seals the bore and performs perfectly at velocities around 800fps. Crank that velocity up to 950+ fps, and you will blow the skirts right off that bullet. You will then have plenty of work to do with the barrel lead removal system of your choice. There needs to be a balance of proper bullet sizing, proper hardness to pressure levels, and condition of the bore............to minimize or eliminate barrel leading. Brian Pearce who regularly writes for Handloader has written numerous articles on this subject over the years.

tdan,

Lead fouling can be a result of the following factors:
1- Bullet size
2- Bullet compostion
3- Load (velosity & powder burn rate)
4- Barrel condition

If 1, 2 & 3 are at correct values obduration is not longer necessary to get a proper fit.

As it relates to cleaning rods, I have not experienced coated rods becoming impregnated like aluminum, although I do make it a habit to wipe the rod with each pass. Unquestionably aluminum rods will take a "set" unlike spring steel coated rods and that alone is enough incentive not to use them. "The fact of the matter is that most folks wipe their rods and use a bore guide." That is not what I have witnessed at public shooting ranges. Most folks buy a Hoppes cleaning kit with an aluminum multi piece rod and have never even heard of a bore guide. "The folks at Pro-Shot that make those highly polished stainless steel rods may take issue with a claim that their rods will harm your bore." Since the stainless that they use in their rods is harder than moly barrel steel it is simply a fact that the will damage the outer edges of the lands. The intention of a bore guide is not to insure that the rod will remain straight throughout the bore it is to protect either the throad area or the crown depending on the type of guide. Properly tight patched jags will result in the rod bowing and rubbing against the bore. If you have ever attended a bench rest match where the shooter are using barrels that, including chambering costs, can run $550+ you will never see an aluminum nor an uncoated steel rod on any of the benches. Thanks for your info on the carbon fiber poles. It is certainly something to think about concerning carbon fiber cleaning rods.

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Doug

PhilOhio,
It's great to hear that you have found an excellent lube formula that works very well in a wide range of applications. It is unfortunate that some of the commercial bullet casters have chosen lube based upon the ease of their manufacturing process without taking in consideration the negative effects that the shooters will experience. It sounds like you enjoy working on all of the facets involved in making and shooting lead bullets in a variety of arms. Keep up the experimentation and enjoy.

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Doug

Guns Magazine April 2011, Page 50

Break the Break In Practice

GUNS Magazine Digital April 2011

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Still Running Against the Wind

Minor correction. It's obturate rather than obdurate.

I have never seen Barsness' name in the results published by the National Bench Rest Shooters Association. Additionally, several of his stated opinions are obtuse to recommendations by many of the precision barrel makers. Opinions do and will differ.

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Doug