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Barrel Break-In Procedure

In Blog by Rich4 Comments

If you’ve been a reader of AccuracyTech I’m sure you’ve heard me joke about barrel break in at some point, just shoot the snot out of it! While that’s true I think it’s time to delve a little deeper into the issue of barrel break in. This is another one of those topics with a lot of lore and legend surrounding it. Most of it stemming from Benchrest and other disciplines of extreme accuracy and anal levels of procedure. For the tactical shooters, we’re a little less about the size of the group, and more about making the hit on the first or second round, anywhere, any time, any condition. So the procedures for barrel break in are bound to be different, that’s not a knock on other disciplines. Merely, it’s a statement of fact, different objectives have different processes.

Barrel Break In

Just shoot it! This has been the long standing joke in the tactical shooting community. Where many in other disciplines have very anal and rigid guidelines for barrel break in, we don’t. Some suggest fire a round, clean the barrel, fire a round, repeat for the first 50 rounds. To the tactical shooter, I say just shoot the gun for 10 or 20 rounds. Run a couple wet patches through the bore just to ensure you don’t have any excessive amount of copper fouling up the barrel, then shoot the rifle some more! Sounds easy, right?

barrel break in kahntrol break

Clean muzzle viewed through the Kahntrol Solutions muzzle break!

Well, it is! Just shooting the rifle is going to do a number of things for barrel break in. For starters, you’re fouling the barrel. The barrel will have different points of impact when it is new and clean and when it is fouled. This is why if you do clean the rifle, always put another five rounds or so through it before you put it away. Put it away fouled so you have a consistent point of impact and zero when you pull it out next time. You don’t want to clean the barrel, put it away, and have to deal with the clean bore versus fouled bore shift when you start shooting next time!

Speeding Up?

Another portion of barrel break in that is relevant, especially to hand loaders, is the issue of the barrel picking up speed. It has been my experience, and that of many other people, across a multitude of barrels and calibers, that most barrels will pick up some speed somewhere in the first 100-200 rounds through the barrel. My experience has been that a new barrel tends to settle in and achieve it’s consistent speed around the 125 round mark. After which any speeding up tends to drop off and before which speed may still be picking up.

Don’t discount this, because it is significant. I shot a match on a new barrel once with around 60-80 through it at the time the match started. During the course of the day the barrel would go on to pick up an additional 200fps over the baseline I had established with a chronograph. I was shooting Copper Creek Ammo at the time and was initially surprised when the first box or two through the gun was coming in a good 200fps under the advertised speed of the ammo from Copper Creek. By the end of the match, I was shooting high on a lot of my shots and scratching my head a bit until I re-chronographed the ammunition. Then I saw the light! By picking up that missing 200fps it had built in a pretty sizeable difference in my DOPE for shots at distance.

Lessons Learned

The point here is, don’t shoot a match on a new barrel, or you’ll be contending with having your DOPE shift around as the muzzle velocity increases as the barrel finishes breaking in. What’s the cause of this? I think there are a number of factors. Minor imperfections in the bore are smoothed out by the passage of projectiles down the bore under pressure and at high velocity. The fouling of the barrel likely has little to do with speed, but a lot to do with point of impact versus point of aim. I think there’s likely some initial movement in the throat area of a new barrel as the first 100+ round pass through it at high velocity.

barrel break in Criterion

Brand new Criterion 6.5 Creedmoor barrel on my AR10!

After these initial variables settle into their final dimensions, or at least final for the foreseeable future, the speed of the projectiles as they leave the muzzle becomes much more stable and consistent than in that initial 100-200 rounds. I’ve heard that several manufacturers won’t even discuss accuracy or velocity questions with customers until they have a minimum of 200 rounds through the barrel. That would seem to make sense in the context of barrel break in and our discussion here today!

Wrapping Up

Remember, while the whole, “just shoot it!” method of barrel break in has merit and makes us all laugh, there is a touch more to it than that. Be cognizant of how many rounds you have through the bore and the likelihood of the barrel picking up muzzle velocity. Be especially conscious of this if you plan to hand load ammunition for the barrel. You don’t want to burn expensive bullets just to get through the initial stages of barrel break in. For that I suggest some cheap, factory loaded ammunition in your caliber of choice. Especially if you can re-use the brass and squeeze some additional value out of the factory stuff you’re using to break in your barrel! As always, if you have questions or something to add, please do so below in the comments!

Owner and Proprietor of AccuracyTech, LLC. Rich is a Firearms Enthusiast, Precision Rifle Competitor, and Writer. He is committed to bringing readers quality reviews and articles related to the Precision Shooting Sports. If you have any questions for him, please use the contact form on the site.

Comments

  1. After reading your article I realize I haven’t put enough rounds through my 20″ 6.5 Creedmore with Bartlein barrel, but am a little concerned that after 60 rounds and following a “break in” procedure that my dopes are consistently going up on all yardages under similar atmospherics. I thought just the opposite would happen as my barrel gets closer to copper equilibrium. I am shooting factory Hornady 140 gr ELD match bullets. I am zeroed at 100 yds and my dope at 200 has gone from .4mil to 1.2 mils, 300 yds from 1 to 2 mils, 500 from 2.8 to 4.1 mils and 800 from 6.5 to 7.1 mils. I clean the barrel after each session but do not use a copper solvent. I have not changed anything on my rig and am using a Nightforce AtacR 5x25x56 F1 mil/mil. Other than reconfirming my zero at 100 and checking the tracking on my scopes, any suggestions on what else to look for?

    1. Author

      How’s the accuracy? Consistent, better, worse than usual? Try giving it a good cleaning. You’re seeing a noticeable drop in velocity there.

      Maybe try a different brand or lot of ammunition to rule that out as well.

  2. The accuracy is consistent at .5-.75 MOA and after shooting, I run a brush, patches and a bore snake through the barrel. Maybe it’s the ammo. Thanks for your input!

    1. Author

      I wouldn’t clean it after every shooting session. That alone can cause issues as it takes several rounds to foul the barrel. During which time your zero could be all over the place.

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