The maintenance of your rifle’s bore has long been a subject of disagreement within the shooting community. I am not sure why this is so as the industry data is clear on the subject. I think in part it is because shooters are desperate to chase the ultimate level of precision and are willing to try some “black magic” in order to achieve it. Some of the myths are simply leftover from old military doctrine or the days when propellant was corrosive and barrel materials were not of the quality and consistency they are now. In this article I will detail some of those myths and discuss bore care commonly used within the industry. I am often surprised that industry does not provide much information in this regard and that may be down to liability and legal issues – If you don’t recommend a bore care protocol then you cannot be liable for it being “wrong”.
The first thing I will discuss is the preparation of the bore in a new rifle. I have seen all kinds of crazy protocols out there, some of which could take up hours or even days at the range and in the gun room. People discuss lapping the bore with projectiles combined with a robust cleaning regime between shots. You cannot lap a bore with a projectile that is softer than the bore material. You could in theory shoot a hardened steel projectile through the bore to lap it but that would be a very risky process! And why would that be more precise than modern engineering tech which is able to cut bores to incredibly close tolerance?
The aggressive cleaning regimen between shots also makes little sense. Cleaning involves either mechanical friction or chemical erosion. You are removing bore material along with any dirt, carbon and copper. There is no need to be reducing a barrel’s life by removing material in the first day of use. I believe this probably comes from times when bores may have had rough or burred sections due to poor engineering processes. Then one could argue that material removal is relevant, it just doesn’t make sense in 2025.
We prepare a barrel for shooting its first rounds by checking the bore by eye for obstruction, gauging the bore for correct dimensional tolerance and pulling a lightly oiled bore snake through to shift any foreign debris. Then we simply shoot the rifle. Luckily for customers the dimensional inspection will have been conducted by a proof house. All you need to do is pull a bore snake through once and then enjoy shooting your new rifle/barrel.
I like to keep a close eye on the performance over the first 100 rounds. I generally take velocities from every shot and I am looking for them to slowly become more consistent. The reason for this is that we are lining the bore with projectile material with every shot. Over 20 or so rounds the velocities will begin to stabilise as the bore becomes a perfect fit for the projectiles you are using. Without lining the bore in this manner, you can get some gas bleeding past the projectile. This can induce some yaw and thus negatively impact precision. It also provides a consistent friction between projectile material and the bore itself. You may wonder if lead-free projectiles have any different effect in this process. The answer is no, they are made of softer materials than the barrel steel and will line the bore in exactly the same manner as a lead core/copper jacket would. The only caveat to this would be when someone changes projectiles. I find the change in material properties and dimensional tolerance can require 5 or so rounds before velocity and precision settles back down again. If you are out hunting this is a consideration as you probably will not be able to take a series of shots to settle the precision back down again.
So if we have ascertained that we can reach a precision plateau through bore lining, the next obvious question is how long does that last? Unfortunately, the answer is not straight forward. It will require some close attention on the user’s part. It will depend on multiple factors – Calibre/ projectile material/propellant quality among others. I have used .308s that would run 400 to 500 rounds before they needed de-coppering. I have had rifles which would run much less. That is your job to watch precision and velocity for changes. Can it be dangerous? Short answer is that nobody in our industry has blown a barrel up because it had too much copper or brass in it. The materials are too soft. The issue will be carbon build-up. Carbon is incredibly hard once it becomes baked on and that can cause pressure issues.
The cleaning regimen I use (as well as many industry guys) is pretty simple. I remove any moisture and loose carbon after a day’s shooting. This can be done with a bore snake and some CLP or with a rod and brush. I do not go to town on it and scrub the bore back to a gleaming state. Plenty of old military guys will want to because that was how they were taught. Just know that when you do that you are degrading the life of your barrel slightly and you will need to fire those rounds to line the bore again and hit that precision/velocity plateau. It serves no practical purpose other than to avoid being screamed at by an angry drill instructor. I have heard a few people discuss propellant being corrosive. Modern nitrocellulose propellants are actually protective to some degree. Old or incorrectly stored propellant can become corrosive as it will leach nitrous acid and nitrogen oxides. Hopefully none of you are using such propellant and if you are you will have bigger problems than a mildly eroded bore. Some of the leeched compounds are explosive and will produce a significant over-pressure when fired. If you have old or incorrectly stored propellant, get rid of it.
Once I begin to notice precision degradation or velocity is climbing I will give the bore a thorough clean. I use a rod and brush along with carbon and copper remover. You should remove these a layer at a time. Carbon shows black on your patch while copper shows green. Keep going until you see no more of either, it can take a while of brushing and patching. Then we are back to our bare bore again. From there I will run a lightly oiled patch through and shoot my rounds until I hit that precision/velocity plateau once more. Now I know I am good for another X amount of rounds until the next major bore clean.