Bore Gazing

By Al Voth on November 25, 2015

Not long ago I was wandering through a local gun show when I saw something interesting on a dealer’s table. I stopped to look and it positioned me beside another browser who was examining a used rifle. As part of his examination, he removed the bolt, pointed the barrel at a ceiling light and proceeded to squint through the bore. His examination didn’t last long and he left before I did. Once he was out of earshot, the used gun dealer behind the table pronounced loudly to his partner, “I don’t know why anyone looks through barrels. It’s stupid. You can’t see anything anyway.” 

This dealer was dead wrong. I considered taking the time to educate him, but thought better of it, as I doubt my efforts would have been appreciated. While I don’t know if the customer gazing down the barrel knew what he was looking for, the incident served to point out that some people have no idea what the inside of a barrel really looks like and what can be learned by examining it. It was disappointing to see a firearm’s dealer as one of those people, but that’s the world we live in.

Safety is the first reason to peek down a firearm’s barrel. Looking down the bore of a firearm prior to use, is a good habit to cultivate. Check down the bore of any firearm before heading out the door with it and if there’s light at the other end of the tunnel, you’re golden.  While I’ve never seen an absence of light in my personal firearms, it has occurred with other guns passing through my hands, where I’ve found spider nests, stuck wads and bullets that didn’t make it out the barrel. Shooting a gun with a barrel obstruction may destroy the firearm and could send you to the local emergency ward too. It’s definitely something to be avoided and checking a bore for daylight at the other end is too easy not to take the step.

However, we can tell other things by looking down a firearm’s barrel too, like if it’s straight or not. Barrel’s are surprisingly easy to bend, a lesson I learned the hard way when a heavy varmint barrel I’d just removed from an action rolled off the bench and landed on the floor. That short drop put a slight bend in the heavy barrel and turned it into scrap. But most barrels are probably bent in hunting incidents, and often there’s a fall involved. A gunsmith once told me the use of quads for hunting and the subsequent crashes involved, gave him a steady stream of business. Fortunately, barrels with minor bends are safe to shoot and they may even shoot reasonably well. However, if it’s a bent shotgun barrel, hitting anything can be a real challenge and if it’s a rifle barrel, all the available adjustment in the scope will be used to get the bullet on target.

Bends are typically subtle and difficult to detect from the outside. Look through the bore, however, and to the learned eye, they become obvious. Looking through any hollow tube at an even light source, will reveal what appears to be concentric circles of light and dark along the wall of the tube. If the tube is straight, these circles will appear perfectly concentric when the eye is centred. But if there’s a bend in the tube, those circles will be misshapen and appear compacted on one side. Since barrels are just hollow tubes, this is how a bend is spotted. The trick is to ignore the rifling when examining rifle barrels—something that’s not a problem with shogun tubes. When buying any used firearm, or even a new one for that matter, a careful look down the barrel will reveal if it’s bent and could save you both time and money.


Corrosion is the next thing to look for inside a barrel, but here it starts to get difficult. Bores are normally dark places and therefore some kind of light source is required. Bore lights, which are nothing more than small flashlights with a plastic “light-bender” attached, work great and are a cheap investment. Even the plastic light-bender alone will often funnel enough light into a bore to provide sufficient illumination. And if none of those are available, put a piece of white paper or a cleaning patch at the other end of the barrel and bounce light off it and into the bore. Corrosion and pitting will appear as dark spots inside the barrel and if visible to the naked eye, the situation is bad. Minor  to moderate pitting won’t be visible at all, although it can often be seen just inside the muzzle where light from both ends can enter.

To see more, we need to enter the world of borescopes. These are optical devices which transmit light down long slender tubes, bounce it off the sidewall’s of a firearm’s bore and direct it back to an eyepiece, where it can be viewed or photographed. Like chronographs, borescopes are steadily getting better and cheaper. A company called Gradient Lens Corp. was the first to develop a borescope of sufficient quality and with a low enough price to be of value to shooters and gunsmiths. Their Hawkeye borescope is now the industry standard, but will still set you back about $700 US. At that price I think they are a necessity for gunsmiths, used gun dealers or other firearm professionals, but unfortunately are still too expensive for any but the most serious hobby shooters. Which is unfortunate, as borescopes are the only way to actually see the inside of a barrel.


Yes, there are cheaper options, but like everything else, you get what you pay for. Although they might never purchase one themselves, shooters need to be aware of this capability and might want to search out a bore scope owner when they think it’s use could be helpful. Borrowing a friend’s is an inexpensive option and mine sees regular use that way. Some gunsmiths offer a borescope examination in their list of services and might even let you take a look at your own barrel. If you ever get the chance, do it. Combining a critical eye, with regular borescope use results in an education. But even if you can’t access a borescope, when you know what to look for, gazing down gun barrels is good practice. Considering you’re just looking through a hollow tube, you can see a lot.