New Barrel Break-in And Cleaning Methods

Len Backus

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I posted this elsewhere in an existing discussion thread but I think it would be helpful to have as a stand alone contribution to the subject. Keep in mind, if you ask 100 barrel makers or rifle builders for their advice on the subject, you'll get many opinions. This is just mine based on lots of study and on my own rifle and shooting experience.

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Here is my take on the subject...and what I give my rifle customers as advice. This is for hand lapped, match grade barrels, not factory gun barrels.

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Long Range Rifles, LLC
Cleaning Instructions



Cleaning Equipment:
Dewey one-piece cleaning rods, jags and brushes are recognized throughout the industry as the very best. I recommend and use them. A properly fitted bore guide is a must and there are many good ones available such as the Tipton Universal bore guide. Bore Tech Eliminator is a non-ammonia copper solvent that we also use for its fast effective copper removal. Under certain conditions ammonia based cleaners can harm a rifle's bore. So we do not recommend their use. Iosso Bore Paste is the only abrasive paste we recommend, and it is for the specific occasional use of removing a carbon build-up in your barrel. Like any abrasive, over-use will damage your barrel. So read more about its use in the general cleaning section below.

Barrel Break-in:
We know that a custom barrel like the Brux Barrels we use at Long Range Rifles break-in faster than factory/production barrels. So what exactly is a broken-in barrel? A barrel is broken-in at the point where it has obtained its maximum accuracy, minimum copper fouling and stabilized velocity readings.

The process of break-in is initiated by shooting just 3-5 rounds and then cleaning your rifle's barrel to remove the copper fouling. Normally repeating this step 2-3 more times will complete the process of reducing copper fouling. During this process, you will notice the barrel is cleaning much easier at every step. With 3-4 cleanings after 3-5 rounds each in the first 25 rounds, go ahead and use the rifle normally, as this part of break-in is complete.

Do not use any abrasive paste type cleaners during break-in as doing this can damage your rifle's bore.

Regarding the aspect of stabilizing velocities, the use of chronographs and experience will show that the barrels tend to speed up over the first 50 to 100 or so rounds, with the exact same load being used during that time period. What does this mean to the average marksman? First understand that your rifle's long range trajectories will change slightly at some point during the first 50-100 rounds. Second, if you're doing load development early on in the barrel's life, (less than 50 rounds) don't max out your pressure or velocity. You may be well over pressure when you hit the 100+ rounds fired mark, caused by a possible velocity increase of up to 75 fps.
At the 75 to 100 round mark, your barrel will now be ready for its first general cleaning.


General Cleaning and Maintenance:
Regular cleaning and maintenance will keep your rifle running its best. This outline is by no means the only way to maintain a rifle. But if you are unfamiliar with the process, this is a good outline to guide you in the right direction.

Make sure your Firearm is unloaded before cleaning.

In general, keep your rifle free of dust and grit build up. Simply wipe off the bolt and swab out the receiver with cloths and q-tips, using a commercial gun cleaner designed for general grime. Similarly, wipe down the outside of your firearm as well. Compressed air also works well for removing dust and debris. Inspect and clean your bolt face with solvent and q-tips, paying particular attention to removing any brass flakes or debris build up around the ejector and extractor. Light oil on a hand towel works great for wiping down your rifle and keeping it looking new. Keep your bolt lugs lubed with a small amount of bolt grease such as TM Ultra and Montana X-Treme. This will help keep the rifle well lubed and prevent bolt lug galling.

Rifle bore cleaning is necessary to keep your rifle shooting accurately. Each cartridge designated rifle may require different cleaning intervals depending on such things as: bullet bearing surface length, bullet velocity, over-bore capacity, cleanliness of propellant used, rate of fire, etc. Normally, experience has shown that anywhere from 100 to 300 rounds are within reason for the frequency of cleanings. Cartridges like the 308 Winchester can go as high as 500 under certain circumstances. Always clean from breach to muzzle.

For general bore cleanings, remove your rifle's bolt and insert a bore guide through your rifle's receiver. Using a properly sized jag covered with a patch, apply Bore Tech Eliminator to the patch and push it through the bore. Always clean from breach to muzzle. This will soften up the majority of bore fouling. Follow this up by running a properly sized bronze or nylon brush through a wet bore for 5-6 stokes. This will help to loosen up stubborn copper and carbon fouling. (Recently I switched to nylon brushes since bronze brushes can give you false positives on the presence of copper fouling.) Continue with more wet patches of Bore Tech Eliminator once every 5 minutes, until your patches come out clean, or with just a faint tint of blue. Usually only two or three wet patches sessions is needed.

Once you are satisfied your bore is free of copper fouling, dry out the bore with some clean patches. If you wish, you can run a wet patch of oil thru the bore, followed by a dry patch to remove the excess oil. This is also a good idea if you plan on storing the gun for a period of time before shooting it again. Make sure you swab out your chamber. I use a bore swab such as the one included in the inexpensive Tipton Action and Chamber Cleaning Kit. It includes a chamber swab and a lug recess cleaning tool. Applying a small dab of quality grease (such as TM Ultra or Montana X-Treme) to your bolt lugs after every cleaning to help to prevent bolt lug galling.

Never fire your rifle without first running a dry patch down your bore to insure you have no bore obstructions, or excessive oil in your barrel.

I always fire two "fouling shots" before I hunt with a recently cleaned barrel – or rely on a shot for sighting in. You will note that the point of impact may be off as much as ½ inch at 100 yards within the first two shots.

Persistent Carbon Fouling
At about every 300-500 rounds fired, we recommend cleaning out any carbon build up in your bore. This can be seen with a bore scope, if available. Or this may be needed if you have an unexplained degradation of accuracy. Carbon typically builds up in the first 1-12 inches of your bore. So this is the area that must be cleaned.

First, clean your barrel with the above outlined procedure for a general bore cleaning, to remove copper fouling. Now we can begin to remove the carbon build up. Iosso Bore Paste may be the most effective way available to remove carbon build up. Iosso Bore Paste is a mild abrasive paste. Coat a patch with a layer of paste, and using a jag and bore guide, push the jag into the first 6 inches of bore, from the chamber end, and stroke the area 3-4 times back and forth. Then stroke out to 12 inches 2-3 times, working back and forth from chamber to 12 inches out.

Lastly, push the patch all the way out the barrel with no back and forth strokes past the 12 inch mark. The patch will be black. This is a reaction with the paste and barrel steel. Don't assume you need to repeat this procedure. Doing it just once has proven to remove 90% of carbon fouling. Now using bore cleaner and jagged patches, push a multitude of patches wet and dry through the bore to remove any and all remaining paste, and once again swab out the chamber.

Over-use of any abrasive in a custom barrel will damage the bore, so follow these instructions carefully and do not overuse.

Firing pin and internal bolt cleaning is best accomplished by a certified gunsmith, special tools may be required for the removal of the firing pin assembly from the bolt. All Long Range Rifles are properly lubed at the shop. If you experience problems with your rifle's bolt and firing pin assembly or have exposed your rifles bolt to excessive dirt, grit or water, have your bolt internals cleaned and lubricated immediately.

Trigger cleaning is normally accomplished by removing the barreled action and spraying lighter fluid or alcohol into the mechanism and then blowing dry with compressed air. Using oil in a trigger can cause a buildup of dust and sludge leading to a possible malfunction. Keep your triggers clean and dry for best results.

Muzzle Brake Cleaning
Carbon build up in a muzzle brake can cause a degradation of accuracy when the buildup gets heavy. Clean your brakes at regular intervals. If you feel a muzzle accessory is causing an accuracy issue, remove it and test fire your gun to eliminate it as a possible source. Soaking and brushing seem to be the preferred method of brake cleaning.

Be careful not to damage your rifle's crown when cleaning muzzle accessories.


Long Range Rifles, LLC


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The step under "Persistent Carbon Fouling" is often ignored and can lead to premature throat erosion IME. I polish the throat every 200-250 rounds depending on how overbore the cartridge is and have found that this step increases barrel life or more specifically the need for setting back the barrel is not needed as soon. I have seen this in 7STW and 7RUM barrels that have maintained accuracy way past the normal accepted round count when keeping the throat polished.
 
Thanks Len. I can definitely attest to both the Dewey one piece rods and Boretech Eliminator. I've also grown very fond of the Montana Extreme Products.

I've also found that just a very slight amount of "White Lube" grease used for high temp/pressure automotive applications is terrific for use on the lugs and raceway.

I'm with you and Zapper as to the "persistent carbon fouling as well". Excess carbon buildup can seriously increase pressures rapidly damaging the first 12 inches or so of a bore and it can happen unbelievably fast once it begins. I unfortunately learned this lesson the hard and expensive way ruining the throats on a couple of .200 Swifts and a .204 ruger.
 
Probably the best write up and compilation of information I've read. Good job. I have found that shooting 1 shot and cleaning for 5 shots gets the barrel most of the way there. 3 and 5 shot groups after that, don't really foul much more than the initial shots. Factory barrels require more work.

I've had about a 50/50 response on using pastes. Some say any form of abrasive down the barrel is premature wear. After obtaining a bore scope and shooing 200 to 300 rounds, I can defiantly see the buildup in the first 6" of the barrel after normal cleaning. Shorter cleaning frequencies helps prevent this.
 
Regarding the aspect of stabilizing velocities, the use of chronographs and experience will show that the barrels tend to speed up over the first 50 to 100 or so rounds, with the exact same load being used during that time period. What does this mean to the average marksman? First understand that your rifle's long range trajectories will change slightly at some point during the first 50-100 rounds. Second, if you're doing load development early on in the barrel's life, (less than 50 rounds) don't max out your pressure or velocity. You may be well over pressure when you hit the 100+ rounds fired mark, caused by a possible velocity increase of up to 75 fps.

Thanks Len. Good stuff here. I just experienced this. I had my suspicions as to the cause, but your Thread was comforting reassurance. I don't break in enough new barrels to identify this any time soon. So your article was much appreciated.
 
Len........that was a very informative and well written article! I also agree with your use of bore tech and iosso as go to products........rich
 
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