My son Matthew and I were recently discussing some brass/copper discoloration he’d found on his Glock G19. “Copper” fouling is usually more present in high-velocity rifles because the high velocities tend to create so much friction and heat it leaves part of the core jacket on the barrel. High-power and bench rest competition shooters fight copper fouling constantly. Some even swear it improves their accuracy.
During my gunsmithing years where I built hundreds of such rifles customers would often come back to me after a few weeks and say “it was super accurate when I first picked it up, but now it shoots worse than my grandmas old varmint rifle. I’d go over cleaning procedures when they picked up their new rifles and show them the specialized odds and ends you use with a rifle of this caliber. But it was rare they’d take it to heart the first time around, but when I cleaned the rifle for them and the accuracy returned they’d become believers. How you break in a barrel greatly affects how easily it will clean. Any decent gunsmith and competition shooter will have their own routine, gear, and chemicals they swear by,myself included. I’ve got a bag of cleaning tricks second to none.
But pistols.. rarely is the problem as serious. Some leading and really minor copper fouling can be present, and relatively simple cleaning procedures lend themselves well in such cases. Later on I’ll do an in-depth article on how to clean a pistol, but for now I just wanted to show you the view from the borescope. Keep in mind that ALL of these pistols had been cleaned using Hoppes #9 solvent, a good condition brass brush, and flannel patches. Each had about ten minutes of cleaning. Most people would think them clean enough.
Borescopes can be so much fun! Ours is relatively new and even has a built in video camera that allows us to share these fun videos. We’re looking at two barrels. The first is a Storm lake and you can see the superior finish. The next is a standard Glock barrel from a G17 and you can see their poly rifling. Both are much more clean, though not perfect. These barrels each have about 45 minutes on them using the exact same method as used on the barrels above, only more of it. It it just me or are you thinking about brushing your teeth?
To the naked eye these barrels and the barrels above look the same. Even using a bore light they look the same. So how to know when the barrel is actually clean? It depends on the bullets you shot, the solvent you’re using, and more. We’ll cover that in depth in our cleaning article.
The point I’m trying to make here is that it’s hard to know when your barrel is properly clean. As you can see there is a huge difference that can destroy your accuracy and eventually hurt your barrel.
One of my bread and butter services while working as a gunsmith was to completely bench strip and properly clean hunting rifles starting 2-3 months before the season opened. My customers would swear their accuracy improved. I believe it did. I’d also check and torque the action screws if necessary, same with the scope, and recommend any other needed services. This was very popular and I was often told they just didn’t want to spend the themselves. Fair enough.
So why this article? Just an FYI, like looking at bedbugs.. hard to see with the naked eye, but damage it being done.