Understanding the Enemy: What is Barrel Pitting?
Defining Barrel Pitting
The term “barrel pitting” describes the erosion of the internal surface of your firearm’s barrel. Imagine tiny, irregular craters dotting the inside of the metal tube. These pits aren’t uniform; they vary in size, shape, and depth. They represent a loss of material, a gradual degradation of the once-pristine bore that the bullet must travel through.
Differentiating Pitting from Other Issues
It is important to differentiate pitting from other potential issues you may encounter in your barrel. Leading or fouling, which is the buildup of lead or other debris from the bullet’s passage, can create a rough surface, but it’s removable with proper cleaning. Rust, identifiable by its reddish-brown color, is another concern, particularly in neglected firearms. Pitting, however, is a more permanent form of damage, and its impact on the barrel’s performance and safety is of primary concern. Finally, bulges represent a severe problem which can be caused by obstructions in the bore.
Visual Inspection
Visually, barrel pitting can range from barely perceptible imperfections to significant, widespread damage. Using a good light source is critical in your visual assessment. The pitting might appear as a scattering of tiny dots, a series of shallow grooves, or even larger, more pronounced cavities. The location of the pitting can also vary, but it’s often found in the throat of the barrel, the area just in front of the chamber where the bullet first enters the rifling. The leade, the beginning of the rifling, is also prone to wear and damage.
The Culprits Behind the Damage: What Causes Barrel Pitting?
Corrosion
One of the most significant contributors is corrosion. Moisture is the enemy here. Exposure to rain, humidity, and even the condensation that forms inside a gun case can lead to rust. Rust then eats away at the metal, forming pits. Improper cleaning practices, or a simple lack of regular maintenance, exacerbates the problem by leaving corrosive residue within the barrel. Using corrosive ammunition, especially without diligent cleaning afterward, can accelerate this corrosive process.
Abrasive Wear
Abrasive wear is another key factor. The constant friction from the bullet’s passage, especially at high velocities, grinds away at the barrel’s surface over time. This wear is amplified when shooting a large number of rounds, or when using bullets that are harder or more abrasive on the metal. Improper cleaning techniques with harsh or abrasive cleaning rods, brushes, or chemicals can accelerate this wear.
Chemical Erosion
Chemical erosion is also a powerful force. The extremely hot gases and combustion byproducts generated when a firearm is fired are corrosive. The barrel steel is subjected to high pressures and temperatures with each shot. Some cleaning solvents, if used excessively or improperly, can also contribute to this chemical attack, removing protective oils and accelerating the corrosion process.
Other Factors
Finally, other factors can play a role. Poor quality barrel steel, manufacturing defects, and even the type of ammunition used can all contribute to the development of barrel pitting.
Assessing the Damage: How to Determine the Severity of Pitting
Visual Inspection
A visual inspection is the starting point. Use a bright light source, preferably a bore light or a strong flashlight, and direct it into the barrel. This will illuminate the interior, allowing you to spot any irregularities. Take your time, rotating the barrel to view all surfaces. Look for any scattering of dots or irregular patches. Observe patterns of wear, or concentrations of pits in certain areas, such as the throat of the barrel.
Tactile Inspection
If you feel safe, you can perform a tactile inspection. Carefully insert a cleaning rod with a clean patch. Move the patch along the bore’s length, feeling for any roughness or snagging. Be very careful, as aggressive handling can cause further damage. Note the location of any resistance you feel. This method is less precise than a borescope, but it can give you some indication of the severity of the pitting.
Accuracy Testing
Another method is accuracy testing. This involves taking your firearm to the range and shooting groups at known distances. As pitting worsens, you’ll notice a decline in the accuracy of your firearm. Groups may open up or become less consistent. You might also experience a change in the bullet’s point of impact. However, accuracy can be affected by many variables (ammunition, shooter, etc.) so it’s important to isolate the barrel as the source.
Borescope
If you are serious about determining the barrel’s condition, consider a borescope. A borescope is a specialized optical tool that allows you to view the interior of the barrel in detail. It can reveal the extent of the pitting, and even take images of the inside of the barrel.
Weighing the Impact: Is the Pitting “Too Much?”
Minor Pitting
If the pitting is minor, it is unlikely to have a significant impact on either accuracy or safety. This level of wear might be considered “normal” after considerable use. The groupings may not have significantly changed.
Moderate Pitting
If you have moderate pitting, the situation becomes more concerning. Accuracy might begin to suffer, with group sizes opening up slightly. You might observe increased fouling (buildup of lead or carbon) in the barrel, requiring more frequent cleaning. The gun’s intended use is crucial here. A firearm for recreational shooting may function acceptably, but for a competition rifle, this degree of pitting is usually unacceptable.
Severe Pitting
Severe pitting is a cause for serious concern. Accuracy will be significantly degraded. You may experience erratic bullet flight or an inability to consistently hit your target. Furthermore, severe pitting could be a safety hazard. It can weaken the barrel, potentially leading to catastrophic failure, especially with high-pressure cartridges.
The Importance of Intended Use
Understanding the intended use of your firearm is critical. A hunting rifle, where accuracy is paramount, demands a higher standard than a plinking rifle.
Actions to Take: Dealing With Barrel Pitting
Prevention
Preventing barrel pitting is always the best approach. However, if pitting has already occurred, you have several options to manage the situation.
Prevention focuses on proper care and maintenance. Always clean your firearm after shooting, using the correct cleaning supplies and techniques. Thoroughly dry the barrel and apply a protective oil. Store firearms in a controlled environment, protected from excessive humidity and moisture. Use appropriate cleaning solvents, and avoid overusing harsh chemicals.
Repair Options
If the pitting is mild, some barrel lapping may help smooth the internal surface and partially restore accuracy. However, lapping is not a complete solution for severe pitting. The benefit of lapping decreases as the pits become more severe.
When to Replace the Barrel
In many cases, the only effective remedy for significant barrel pitting is rebarreling. This involves removing the old barrel and replacing it with a new one. This is the most reliable way to restore both accuracy and safety. Consult with a qualified gunsmith to determine the best course of action.
Seek Professional Help
Finally, when your barrel’s condition is in question, seek a professional opinion. The expense is insignificant compared to the value of your personal safety.
Conclusion
Barrel pitting is a fact of life for any firearm owner. A few pits here and there are acceptable. However, understanding the causes, recognizing the signs, and knowing how to assess the severity of the damage will ensure your safety and help you make informed decisions about the lifespan of your firearms. Remember, if you’re in doubt, seek professional guidance.
Good shooting!
