The Carbon Ring - Inside MDT

Posted by Matt Hornback on 2023 Aug 3rd

The Carbon Ring - Inside MDT

Rifle cleaning has been a long-debated topic with some interesting opinions and methods. The debate over the years has brought forth an entire segment of products in the firearms industry, many of which claim to be "the solution" to cleaning and maintaining your firearm. But at what point do these products NOT work?

Through the years, my cleaning process and frequency have evolved with my knowledge of how rifles and ammunition work harmoniously to yield the best results possible. Gone are the days of buying a cheap box of ammo and cleaning when "the accuracy drops off." With matches and hunting trips delving in the thousands of dollars each trip, it is of utmost importance that your rifle and ammunition are working together as they should.

WHAT IS A CARBON RING?

Enter the carbon ring. Some have heard of the carbon ring problem that rifles can develop, but few shoot enough to see the effects. In my precision rifle shooting career, I've burned out a couple dozen (or more) rifle barrels of various calibers but never encountered this problem before. I've heard of the many different ways to cure or combat the issue and what the negative effects could be, but I have gotten lucky until now.

When I arrived in South Dakota, my local guide and best friend, Josh Cluff of HS Precision Rifles, took us to a large pheasant hunting farm with a gorgeous private range facility the day before the match. We set up chronographs and doped our rifles out to 1100 yards with relative ease, as I was able to hit any part of the target I desired.

More: Expert Gear Guide for Precision Rifle Competition

Day one of the 2-day Precision Rifle Series, Target hanging Solutions Match, and we were off to the races. The first stage of the entire match consisted of 5 IPSC silhouettes out to approximately 750 yards, shot off of a rooftop. On the beep, I built my position on the rooftop, closed the bolt, and with a gentle press of the trigger, my bullet went 1 MIL high over the target. I checked my dope on the turret and sent another 1 MIL over the target again. I transitioned to target two and sent two rounds well under the target. I then knew something wasn't right. I attempted to make corrections for the remaining targets on the fly but ultimately came up with 0 points to show for my efforts. It was time to head to the zero board and see if I could figure out the problem.

Upon firing three shots at the 100-yard zero bards, I noticed that the rifle was zeroed but was shooting very erratically. I decided to roll with it and see what I could manage. What I encountered for the rest of the day was battling elevation issues at every stage with inconsistent results. After day 1, I sat in a lackluster 70th place. Day 2 rolled around, and I was bound, determined to fight my way back up, but after time out on the first stage, I extracted a live round from the chamber, and that's when I saw substantial marks on the bullet bearing surface. This is a tell-tale sign that there was, in fact, a carbon ring in the chamber causing my issues.

Note the marks on the bullet from the Carbon Ring. If you see this, you have a Carbon Ring that needs to be dealt with.

Squad mates helped me by loaning me bore cleaning solvent, patches, and brushes. I attempted to clean out the carbon ring the best I could in the parking lot before shooting the next stage. I was able to knock some of it down, but the effort was futile. My rifle went right back to where it was in a matter of a few rounds. I spent the rest of my day battling wind and elevation, which is a fight you'll lose every time. I ended up in 84th place out of 118 shooters.

The frustration on my face was obvious in this photo.

CARBON RINGS AND VELOCITY AND CHAMBER PRESSURE

Carbon rings profoundly affect velocity and accuracy as the bullet makes a near-perfect seal into diamond-like hard carbon. This seal dramatically alters chamber pressures and will increase velocities resulting in DOPE issues. The bullet contact is far from where load development was done and thus creates erratic groups that make it almost impossible to hit targets at a distance.

When I arrived home, I immediately removed the barrel and ran a bore camera down into the chamber and found a massive carbon ring; this build-up occurred with less than 1300 rounds on the barrel. The particular barrel is of the highest quality and cut-rifled; the cartridge is a 6.5 Creedmoor, shooting match bullets and using a modest load of H4350. A proven combination that I've been shooting since the beginning. For the past two years, my cleaning routine has been using a very well-liked 2-part cleaning product that I thought had been doing an excellent job. I would clean following every match, and my barrel never went more than 200 rounds before being cleaned.

Carbon Ring and an empty brass casing.

Carbon Ring no brass.

After talking to many other shooters, I narrowed it down to a few new-to-me products to try and cure my carbon ring issue. CLR (the household cleaner), Bore-Tech Eliminator, and JB Bore Paste were common answers. I ordered some Bore-tech and CLR and gave them a shot. Using both products on the problem barrel yielded positive results, but the hardened carbon is far from erased. After a solid day's worth of soaking and scrubbing, I finally got the throat to not leave marks on the bullet upon chambering. I wouldn't call this solved just yet, as I will follow this regiment up with JB bore paste to see if I can remove any more of the carbon build-up.

As for this barrel, I'm calling it a practice barrel from here on out. From now on, I will soak the throat area of my match barrels with either Bore-Tech or CLR, narrow down which works best, and then confirm every cleaning with the borescope. I cannot leave any chance of this happening again after all the detailed work and preparation it takes to compete at large national matches.

The Carbon Ring is gone after a thorough cleaning.

Update 7/30/2023: After thoroughly cleaning the barrel with Bore-Tech Eliminator, CLR, then JB Bore paste, the carbon ring is gone, and the barrel is back to shooting 1/2 MOA groups. The barrel will be used in an upcoming local match.

COMPETITION AND HUNTING RESOURCES FROM MDT

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