Why You Should Have a Borescope - Inside MDT

When you stare into a 'clean' rifle bore, everything looks bright and shiny. But it's all a matter of perspective and scale; even sandpaper appears smooth at arm's length. A closer look can reveal problems that cause poor downrange performance. To get a better understanding of my bore, I recently upgraded to a digital borescope, a camera that sends crystal-clear images to my phone, and it has been enlightening!

Before getting a borescope, I would observe the bore from the muzzle or chamber using a bore light. Using this basic diagnostic, I've encountered new barrels with rough tooling marks and old guns with neglected bores. However, in my relentless quest for higher performance, I needed a closer look, and a borescope was the answer.

A borescope allows you to inspect the bore of a new rifle.

Borescopes were once relatively pricey, enough so that I didn't make them a priority purchase. But times and technology have changed. Today's digital borescopes are affordable and include the option to take photos or video while delivering the clarity of higher-priced optical borescopes. Given the insight these tools provide, it was time to invest in a powerful diagnostic tool. I chose a Lyman Borecam 2.0 for its features, price, and utility. My Borecam provides critical intel, and here are my top four reasons for using it regularly.

INSPECTING NEW BARRELS

By inspecting the bore of a new rifle, I can quickly identify any problems that may have slipped past quality control. Production rifle barrels are more likely to have problems than barrels from aftermarket and custom barrel makers. Still, it's good to examine the finished surface of the bore. I check for reamer marks and flaws in the rifling. Next, I inspect the chamber and throat area, looking for a smooth finish and a concentric chamber. The first few times you look at these details, the results may shock or even scare you; it did for me. However, it's important to keep things in context—we are looking for the big things that can affect barrel accuracy.

The Lyman Borecam 2.0 features a 26-inch graduated rod, which comes in handy for pinpointing any problem areas. Digital borescopes take pictures and videos. If I find a major flaw or defect, I can capture an image or record a short video of the problem. With documentation, it is easier to request service or warranty repair. Owning a rifle with a factory defect can be frustrating; I've certainly encountered a few lemons.

The borescope can either view straight down the bore or, using a mirror, provide a 90° view.

Minor tooling marks are common in factory barrels, and lapping can smooth them out, reducing fouling and increasing the time between cleanings. If you choose to do it yourself, borescopes can help monitor progress.

ASSESSING FOULING

All rifles need periodic cleaning, more so when shooting corrosive ammo. I use a borescope during my routine rifle maintenance, and I also use my borescope to check how fouled the bore is when accuracy falls off. It also indicates if my solvent and cleaning technique is working, getting through copper and carbon fouling down to the bare metal. One quick pass with the borescope, and I see the fouling on the lands and grooves. It also shows if chemical cleaning is getting the job done and when I need extra elbow grease with a brush.

A close-up view of the rifling shows carbon deposits.

ASSESSING WEAR

Bore wear is an inevitable part of shooting. Hot gasses crack the bore and erode the rifling directly in front of the chamber. Wear occurs quicker in magnum cartridges or in high-volume shooting when the barrel isn't allowed to cool down between groups. I'm sure every new borescope owner is shocked to find fire cracking and rifling wear. Again, keep things in perspective. Seeing wear can indicate how much barrel life is left, but let the groups on paper be your guide. On a worn barrel, handloaders can play with load charges and bullet seating depth to restore and extend barrel accuracy. If this doesn't help, it may be time to get a new barrel.

The leade and rifling are sharp and clean in this Savage Impulse Elite with MDT Chassis.

INSPECTING USED FIREARMS

Buying a used gun can be a crapshoot. An ability to inspect the bore, especially on competition guns, military surplus rifles, and muzzleloaders, can make the difference between buying an inaccurate wall hanger and a quality, functional firearm. A borescope reveals rust-pitted bores, worn-out barrels, and factory flaws (that may be why the gun is for sale in the first place). Many hunting rifles have relatively low round counts and can be a great deal on the used market. Conversely, it can give you the confidence to buy used, save some cash for upgrading the factory stock to an MDT Chassis, and feed your 'new' baby with ammo.

Old hunting rifles usually have low round counts. Still, there is fire cracking in this 7mm Rem Mag barrel.

BONUS: BRASS INSPECTION

Handloaders know that all brass has a finite lifespan. Depending on the cartridge, brass quality, chamber dimensions, charge weight, brass preparation, loading procedures, and other factors, you can expect 6 – 12 (or more) loadings per case. Loose primer pockets, cracked necks, and case thinning above the web (leading to case-head separations) tell signs it's time to retire the case. Case thinning is most evident on the inside. Some shooters use a bent paper clip to feel for this problem. However, a borescope makes it easier. At the same time, looking inside the brass can expose flash hole problems that need fixing. Does clean brass shoot better? I don't think so, but others disagree. If you want like-new cases inside, use a borescope after cleaning to see how it looks. Finally, scoping it adds an extra safety check if you like to scrounge range brass.

More: Scavenging Brass

CONCLUSION

At one time, I didn't know what I'd do with a borescope. Now, I'm not sure what I'd do without one. For the precision shooter, it is a powerful diagnostic tool on the road to higher rifle performance and a valuable tool in the toolbox.

HARD SKILLS AND KNOWLEDGE FROM MDT

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• 5 Things to Know Before Buying a Suppressor
• Five Common Questions About NFA Items
• Swapping Barreled Actions From Chassis to Chassis
• Brownells Quick Tip Assembling a Howa Rifle
• Reloading Crimped Brass
• How To Remove A Tikka Barrel
• DIY $6 Target Stands - Guns And Guitars
• Do Muzzle Brakes Affect Group Size?
• All About Primers
• Reloading Crimped Brass
• Scavenging Brass
• King of the Coyote Calibers
• Tag Your Hunting Truck
• The Ethical Shot
• How to True Your Ballistic Coefficient
• Traveling to Canada With a Rifle

ABOUT THE AUTHOR

Lowell Strauss began shooting at a young age, eliminating pests from his family's farm. Later he started hunting, then offseason target shooting. His fascination with guns and how they work led him to join the Canadian Forces Primary Reserves, where he trained and served five years as a Weapons Technician. Lowell is currently a hunter and firearms safety instructor, target shooting and biathlon coach, and a full-time freelance writer and photographer focusing on shooting sports and the outdoors. IG and Facebook: @straussoutdoors @theBallisticsLab