The Ins and Outs - Handgun

Barrel Wear

When is a barrel shot out? It’s a simple enough question, but one that has many different answers. This answer should depend on the level of accuracy and performance the shooter expects from the firearm. Naturally, the expectation for match competition are going to be higher than one used solely for big game hunting. In the final analysis, the shooter must decide for himself.

Certain cartridges will prove harder on barrels than others thus greatly affecting the accuracy life. Putting it simply, a barrel is washed out by “X” pounds of powder. Whether it’s spread out over many small charges or a smaller number of large charges, it’s still “X” pounds of powder. For example, a 357 Magnum revolver used only with 38 Special mid-range loads will have a longer accuracy life than an otherwise identical revolver used only with heavy magnum loads. This is simply because of the lower operating pressures and the fact that we’re using less powder per round.

Heavy loads in intense cartridges will erode the throat of a barrel much faster than milder loads in the same cartridge. Nonetheless, most shooters who purchase magnums do so for the extra terminal performance and are hesitant to use reduced loads. This is unfortunate, as these loads are much more pleasant to use, generally more accurate, and much easier on the gun. Do yourself a favor and try some of the milder starting loads shown in this manual, particularly for those situations that don’t call for top-end ballistic performance.

Components

The reloading components available to today’s handloader are the finest the sport has ever known. Modern powders are much less erosive than those used by past generations of reloaders. Bullets are now jacketed with gilding metal alloys that don’t foul bores nearly as badly as the older cupronickel jackets did. Primers, however, are undoubtedly the single biggest improvement as far as barrel life is concerned. While most handloaders have heard primers referred to as “non-mercuric” and/or “non-corrosive,” few (who have been shooting less than 50 or 60 years) have a real understanding of what these terms really mean.

Corrosive primers used potassium chlorate as the oxidizer in the priming compound. When ignited, the potassium chlorate produced potassium chloride, a compound very similar to common table salt. Like any salt, it attracted and held moisture. This moisture, in turn, caused rusting in very short order. The old frontiersmen had a saying, “the sun must not set on a dirty gun.” This was a direct reference to the absolute necessity of cleaning a gun almost immediately after firing it, because of the corrosion problem. Leaving it for a few days simply was not an option. Once potassium chlorate was identified as the cause in the corrosion problem, it was replaced, leaving us with the “non-corrosive” primers we enjoy today. Fulminate of mercury was one of the more popular initiators used in early primers. When jacketed bullets and smokeless powders became widely accepted near the turn of the century, operating pressures increased drastically for the average cartridge. With these new higher pressures, handloaders soon found that cases frequently became extremely brittle after the first firing, rendering them useless for further reloading.

The culprit was the mercury in the primer. Upon firing, the mercury amalgamated with the brass case and chemically attacked it, causing it to become brittle. Primers that were made without fulminate of mercury eliminated this problem. These primers are referred to as being “non-mercuric.” While not specifically a problem as far as bore erosion is concerned, mercuric primers are discussed here because of their close association with corrosive primers. Today, virtually all U.S. made ammunition and component primers are non-mercuric and non-corrosive. Corrosive and/or mercuric primers may still be encountered in surplus ammunition from former Warsaw Pact countries and in foreign-type surplus military ammunition manufactured prior to WWII.

Erosion from Propellants

With the passing of corrosive primers, erosion from the propellant itself is undoubtedly a barrel’s greatest enemy. When the powder is ignited, it creates extremely hot gases under tremendous pressure. These two factors combine to create erosion, particularly in the throat area of the barrel. Intense loads operating at extremely high pressures will erode throats faster than milder loads, of course, but flame temperature is another factor that is seldom considered. Certain double-based powders that have extremely high flame temperatures can accelerate throat erosion if they are used to excess. This is something of a “Catch-22”, in that several of these powders provide the best performance from some magnum handguns. The solution here seems to be to use lighter loads whenever possible, reserving the heavy loads for occasions that really call for the extra power. Rapid firing, which develops extremely high temperatures in the barrel, will also exacerbate this situation regardless of the powder type being used.

Improper Cleaning

It is a sad fact that with the vast improvements in better barrel steels, non-corrosive primers, and less erosive propellants, probably as many of today’s barrels are ruined by improper cleaning as by neglect. Careless use of a cleaning rod, failure to use bore or muzzle guides, improper use of harsh solvents, or the use of poor quality or badly maintained cleaning equipment all can do more harm to a firearm than no cleaning at all. This need not be the case, and the few minutes it takes to learn proper cleaning techniques is time well spent. There are several specific types of fouling, each with its own set of problems, which need to be addressed separately.

Metal Fouling

Metal fouling may refer to either lead or copper buildup within the bore. This fouling is the result of the friction, pressure and high temperatures that are inherent in firing. Guns will vary a great deal in their tendency to foul, depending on such factors as the smoothness of the bore, the fit between the bullet and bore, jacket hardness, and intensity of the load.

Copper fouling is normally seen as a copper “wash,” sometimes plainly visible on the surface of the bore. Despite its rather innocuous appearance, this fouling can seriously degrade a barrel’s accuracy potential. While removing this fouling can be tedious, it must be done to maintain top accuracy.

Fortunately, today’s shooters have perhaps the best assortment of truly effective copper solvents ever available.

Lead fouling, also called “leading,” is usually much more noticeable, frequently as a lumpy buildup at the throat or forcing-cone area of the barrel. Being an extremely soft metal, lead is seriously affected by the stresses of high-intensity loads. Unless carefully cast from a suitably hard alloy and lubed with an effective lubricant, lead bullets are best reserved for lower-pressure loads and reduced velocities. Once leading has begun, successive bullets passing over a spot in the bore already affected by these deposits will quickly worsen the condition. This, in turn, will cause an immediate and sometimes serious loss of accuracy unless removed.

Powder Fouling

Powder fouling is the result of the combustion of the powder that leaves an ash, or residue, in the barrel. In extreme cases, it may take the form of a carbon buildup. Powder fouling can generally be removed without much difficulty by milder solvents and a good scrubbing with a bronze brush.

Bullet Friction

Bullet friction, as it relates to barrel wear, is frequently a topic of discussion among shooters. While friction may cause some wear, it is the least measurable factor in barrel life. In Small Arms Design Vol. II, Col. Townsend Whelen mentions a Springfield 22 rimfire barrel that had been gauged when it was installed, and again after having fired more than 80,000 rounds. A uniform wear of .0004" was observed throughout the length of the bore, undoubtedly caused by bullet friction. Granted, this was referring to lead bullets, not jacketed. However, when we consider the wear and tear that most handguns will take over their career, 80,000 rounds is an awfully long life for a barrel.

There is perhaps one situation where bullet wear may pose a problem —poorly made lead bullets cast from dirty material. If the dirt and grit commonly found on used wheel weights and other sources of scrap lead is not removed by frequent and thorough fluxing, it will be cast into the bullets. Any grit exposed on the bullet’s bearing surface will act as an abrasive lap. This situation is easily prevented with some common sense and good casting techniques.

Proper Records

The simple answer to these problems is to maintain a logbook for each firearm. This may be a small logbook specifically designed for the purpose, such as those marketed by Creedmoor Armory, or simply a 3" X 5" note pad found in any business supply or stationery store. The notations need not be extensive: date, number of rounds fired, and perhaps the type of firing (match, load development, hunting, etc.

You may also wish to note the type of cleaning technique used, especially if you are doing something other than your normal routine. This is perhaps the best way to make valid conclusions about the various types of bore cleaners available and the best ways to use them. This also helps identify any developing trends in fouling patterns in a particular barrel. These changes can help alert the shooter to a problem with the bore — be it erosion, etching or other physical damage.

Perhaps the best reason to maintain an accurate logbook is that it might save you the cost of a barrel. If you have a barrel whose accuracy has noticeably deteriorated, yet the logbook reveals a relatively small number of rounds fired through it, the bore probably isn’t shot out. In these cases, the problem might be resolved by a more thorough cleaning, perhaps using stronger methods than previously used. If the barrel isn’t fouled, and the logbook tells you that it should not yet be shot out, the problem may be in the gun itself; the timing (in a revolver), the crown, your loads, etc.

Most shooters tend to badly overestimate the number of rounds they’ve fired through a particular barrel, leading to the premature conclusion that the bore is shot out. Many of the “shot out” barrels that are replaced these days could be completely restored with a good cleaning. Considering the cost of rebarreling (especially when dealing with a top pistolsmith and an after-market custom barrel), it’s well worth the time it takes to record this important information.