The Dreaded 22LR Carbon Ring

| September 24, 2022 | 0 Comments

What Is A Carbon Ring Does It Have Any Effect?

Author RickBaum of RFC

First of all, I’d like to explain that I am not an industry expert. Nor do I have a degree in anything carbon ring related. All I have is my personal experience and what I have read. I am the kind of person that if told something, or I read it, I like to verify that information with personal experience.

Here’s what I’ve learned, take it for what it’s worth.. I’ll do my best to cover the 3 subjects below.

What is a carbon ring in a 22lr rimfire?

What effect does a carbon ring have?

How to get rid of a carbon ring?


My History Of Dealing With The Carbon Ring

About 4 years ago I became involved in competitive shooting, specifically 22lr. Even though Ive owned and shot a 22 since I was 11, I had only thought about cleaning it when it wouldn’t properly cycle and return to battery. (Marlin model 60) That is until I got into competitive shooting. My first competition rifle was a CZ 455 Varmint. I got really lucky, in that it was a real shooter! That Is, it was a shooter until I got about a brick through it! Then something weird happened.. At my matches, after the rifle sat idle between stages, the first shot would hit high left, about an inch from the rest of the string if we were shooting 100 yds targets. If shooting a closer target, say 50 yds, it might be only a half inch high and left. I scratched my head over it and searched the internet until I found an article written by someone (Steve Boelter) that sounded like he knew what he was talking about. In the article, the gentleman talked about a carbon and lead buildup in the chamber of a 22lr. That buildup gets thicker and thicker until it swages the bullet as it is chambered. Here’s the part that didn’t make any sense to me and made me buy a borescope to literally “see” for myself what was going on. He said that after the first round is swaged and fired and subsequently misses the POA, the “ring” gets heated enough that it softens and won’t swage the following shots of a string of fire. First, he described exactly what I was experiencing. And second, how could carbon and lead soften from one shot? So, I bought a Lyman borescope and took a look in my chamber. Sure enough, there was a very definite buildup of jagged black nastiness right about where the end of a case would be in the chamber. So, to test the theory, I soaked, scrubbed and cleaned until I saw nothing but bright shiny metal in the chamber.

I couldn’t wait to go to the range and see what effect, if any, cleaning had on the “cold bore” fliers that I had been experiencing. So, off to the range I went. After about 15 or 20 shots to refoul the bore, I was back to my normal accuracy. Now it was time to wait for things to cool down. In my matches, there would be anywhere from about 15 minutes to a half hour between stages, so I found something else to do for a half hour… After the wait, I loaded a mag and chambered a round. Took aim at a paper target at 50 yds and fired. Okay, first shot seemed to go where I wanted it to. So I fired 9 more. All in a nice tight group without any fliers! Boy, was I relieved. I repeated the “wait and cool” experiment several more times that day and every group was without the exaggerated flier that I had been experiencing. I was stoked! I had no idea how many points I had missed out on because of those cold bore fliers, but I had them figured out now!


What I learned Using A Bore Scope

Now that I owned a borescope, I used the heck out of it to check the results of my cleaning. I was never finished cleaning until the last speck of the ring was gone!

One thing I’d like to add to what the gentleman wrote in that fateful article… I don’t know exactly what the chemical composition of a 22lr carbon ring is, but I can tell you this after paying attention for several years now. The lube on our match grade bullets is a big part of the equation! A very BIG part! I noticed this after having watched “normal” rings grow from shooting matches. Then, I bought my first Lilja barrel. After installing it and taking it to the range to ammo test it with multiple brands and grades of ammo, I looked in the chamber and there was the nastiest ring I had ever seen! It literally looked like jagged, bubbly, solidified lava! I thought maybe it had something to do with the new barrel. Maybe I hadn’t cleaned it well enough before shooting, or something. So, I cleaned it back to bright shiny metal, went back to the range and repeated the test. Same carbon ring result! So I cleaned it and went back to the range, fired the same number of rounds, but only one brand of ammo. I wanted to see if the mixing of lubes was causing it. So, there was a ring, but it was a “normal” looking ring. So I cleaned my rifle again, went back to the range, fired an equal number of rounds, all of another brand, and again, normal ring. Cleaned it, went back to the range, and shot a mix of ammo brands and the nasty ring was back.


What I Learned From This Experiment

This experiment taught me 2 things..
1. When ammo testing, only shoot 1 brand of ammo at a time, and just swabbing the barrel prior to switching brands/lubes, does very little to prevent the “nasty ring”!
2. This is the most important thing that I learned. At least to me it is. Carbon rings are not JUST lead from the bullet and carbon from the combustion process shooting multiple rounds. Carbon rings are heavily effected by the lube on our bullets. A carbon ring will build without lubed bullets, but the lube contributes to the ring in it’s own way.

When I said that lube contributes to the ring, I would also add that the type of lube on the different brands of ammo builds up at different rates! I started tracking how many rounds I could fire before I would start experiencing cold bore fliers. What I discovered is that my then favorite brand of ammo, RWS R50, would allow me close to 150 rounds before things would go south. Lapua CenterX will go twice as many shots before I experience fliers. It’s actually a little more than twice as many. I can get about 325ish shots down range before I see fliers. I haven’t experimented with Eley, but I would expect something similar to R50, since their lube is more waxy like R50’s.


The Dreaded Ring And Its Impact

The next subject is “what effect does a ring have on a round/shot taken”?

I have come to think of a carbon ring as something like cooking sugar. By that I mean that, if you’ve ever been in the kitchen when someone is making carmeled popcorn balls, you heat up a bunch of sugary ingredients to the point of it becoming liquified. It cant get too hot, or when it cools it will be too hard and brittle. But with sugar that is brittle, it can be reheated until it becomes malleable or even liquid if you really get after it. However, when it cools it will harden and be brittle again. Carbon rings behave in a similar way. When hot, they are malleable, when cool they are very hard.

So, with a well built up and hard ring in your chamber, when you chamber a bullet it gets squeezed and shaped as it passes over or through the ring. You end up with a deformed bullet that doesn’t have the same aerodynamic characteristics of a nice, pristine, concentric bullet would. If squeezed enough, it may not seal the chamber and you’ll lose pressure. I can only hypothesize why these deformed bullets tend to hit the target at a relatively consistent POI away from POA. But in my experience, they do tend to do just that.
Anyway, back to the ring’s effects.. After that first shot, the ring gets warmed enough that it doesn’t squeeze or swage subsequent shots in the string and the shots group normally. Let things cool down and you’re back to the first round rebel straying away from the norm.

My Love Hate Relationship With The RING

Methods for cleaning a carbon ring is something that I’ve laughed, cringed, and rejoiced over.

During my “battle” of carbon rings over the years, I’ve tried a lot of things to get rid of them. It was a mechanical battle at first. Sometimes it took inordinate amounts of standard bore solvent and brushing to get rid of one. I thoroughly understood how a person could do more harm cleaning their rifle than by firing it ever would! There had to be a better way… I stumbled on to what I feel is the best way when I consulted Don Smith (djdilliodon) to see what he recommended for cleaning rimfire rifles. He suggested a product called Bore Tech Rimfire Blend. So, I bought some and tried it. I have to say that it smelled awesome, kind of citrusy. But it didn’t do any more damage to a carbon ring than Hoppes or Butches Bore Shine did. At least it smelled better! Then as I was perusing a local Scheels gun department, I saw a bottle of Bore Tech C4 Carbon remover on a shelf, so I bought it just to see if it worked like it said it does on the label. To make a story short, I found my Excalibur to fight carbon rings. Wet a patch, insert it into the chamber, leave it to soak for 15 minutes or so and it totally dissolves to ring! NO MORE SCRUBBING!! Occasionally I have to do a second soak, but I never have to scrub now. And to me, the fewer passes of a cleaning rod in my barrel, all the better. Less chance of damaging a crown or throat or…

Borescopes… If you care about ultimate accuracy, and you don’t own a borescope, I highly recommend that you get one. If for no other reason, just to keep tabs on the effects of your cleaning regimen. They come in handy for inspecting crowns and all kinds of things not gun related as well.

I started off with a Lyman. It will allow you to see everything that you need to in a barrel. I’ve since upgraded to a Hawkeye. DJ’s hawkeye to be precise.. Thanks again Don! It really doesn’t matter what scope you get, but I do recommend that it is capable of a 90° view so that you look straight down on your chamber or bore. I can’t make things out as well if I’m looking straight down the pipe. YMMV

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