Barrel Break-In

hbean said:
Google is your friend. read and note the very last sentence!
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The OP asked about an AR15 barrel. The googles is a bad, bad place for real information. Try talking to someone that makes barrels. The best source for the OP would not be CGN, but rather Bushmaster directly.

Most AR15 barrels are not made as described above. Many higher end military barrels are hammer forged, like Cold Canada, HK and Daniel Defence. CC barrels have the Diemaco process forging that makes the chamber at the same time - no reamer at all. Button rifled barrels, such as Colt are also not made this way. The blank is rifled and then chambered. Engineered chrome barrels (most AR barrels) are acid etched prior to plating which would reduce any tool marks. The hard chrome itself is rough and the only thing that smooths it out is firing. And Milspec barrels like Colt and FN are all test fired at the factory.

Coppering does not occur in a chromed barrel as described above for bare metal bores.

As for specialized match barrels, like my stainless national match barrel, any match barrel that was chamber reamed and leaving reamer marks is not a real match barrel, and no amount of patches will fix that. Most of these are button rifled, but the steel is selected with care to reduce chatter and other undesirable marks. Many are lapped as well. he cut ones are also produced with care. I also have hammer forged match barrels (non-chromed) for which the break in procedure is this: remove oil and commence firing.
 
mikethebike said:
So we have krieger that says to do it
Mcmillan that says it is useless
John Noveske that says that its useless
Colt Canada that says its useless
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Careful how you read it, Krieger and Bartlien both are saying each barrel is different some break in, might take one or two rounds all depends on the amount of the copper you see on you patch after the first couple of shots. Both Krieger and Bartlien are precision barrel maker where users are concern with sub MOA deviations from fouled barrel, with an AR you are dumping hundreds of rounds per shooting session, a bit of fouling is not something a typical AR user worries about.

taken from Bartlien Barrels' FAQ said:
The age old question, "Breaking in the New Barrel". Opinions very a lot here, and this is a very subjective topic. For the most part, the only thing you are breaking in, is the throat area of the barrel. The nicer the finish that the Finish Reamer or Throating Reamer leaves, the faster the throat will break in.

Shoot one round and clean for the first two rounds individually. Look to see what the barrel is telling you. If I'm getting little to no copper out of it, I sit down and shoot the gun. Say 4 - 5 round groups and then clean. If the barrel cleans easily and shoots well, we consider it done.


If the barrel shows some copper or is taking a little longer to clean after the first two, shoot a group of 3 rounds and clean. Then a group of 5 and clean.


After you shoot the 3rd group and 5th group, watch how long it takes to clean. Also notice your group sizes. If the group sizes are good and the cleaning is getting easier or is staying the same, then shoot 4 - 5 round groups.


If fouling appears to be heavy and taking a while to clean, notice your group sizes. If group sizes are good and not going sour, you don't have a fouling problem. Some barrels will clean easier than others. Some barrels may take a little longer to break in. Remember the throat. Fouling can start all the way from here. We have noticed sometimes that even up to approximately 100 rounds, a barrel can show signs of a lot of copper, but it still shoots really well and then for no apparent reason, you will notice little to no copper and it will clean really easy.


This is meant as guide lines only. There is no hard and fast rule for breaking in a barrel.
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1feral1 said:
'But believe what and who you want'... 'yes myth'.

Dude, in professional militaries, for maintenance of equipment including weapons, we follow guidelines set forth at command level, which are adhered to to ensure quality of maintenance and modification of such equipment, where the 'running in' of barrels in specific weapons is required. There's no myth about that.
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Having served in a professional military, I have seen guidelines set forth for firearms maintenance that are not only useless, but damaging to the weapons. The military is particularly rife with examples of "we've always done it this way" syndrome, and shouldn't be unquestionably taken as any sort of end-all be-all.

As a soldier, you do what is required of you, even if it is not optimal.
 
Jarvy said:
Having served in a professional military, I have seen guidelines set forth at command level for firearms maintenance that are not only useless, but damaging to the weapons. The military is particularly rife with examples of "we've always done it this way" syndrome, and shouldn't be unquestionably taken as any sort of end-all be-all.
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Under the Corps of Electrical and Mechanical Engineering in policy research and establishment?? Kindly explain some examples you think are/were useless. I'd like to know. I simply follow instruction laid down in written guidelines, and the rifles worked as they should have, all within the tolerance of accuracy required.
 
1feral1 said:
Under the Corps of Electrical and Mechanical Engineering in policy research and establishment?? Kindly explain some examples you think are/were useless. I'd like to know. I simply follow instruction laid down in written guidelines, and the rifles worked as they should have, all within the tolerance of accuracy required.
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I don't exactly have access to Australian military documentation, nor the inclination to rummage through them for specific examples. I mean, aside from the one you so helpfully provided.

The fellow who makes the barrels for the Canadian (And France, America, South Africa, Israel etc) military's precision rifles says the break in procedure does more harm than good, and makes a compelling argument. No doubt the fellow who makes the barrels for the Aussie equivalents advocated a breaking in procedure. Maybe because he legitimately thought it helped, more likely because he thought it'd get him future contracts for more replacement barrels. I know who's word I would take in any case.

As a soldier, I agree, if the guidelines were to break in the barrel of a rifle, I would do it as required. I may attempt to get the procedures formally changed, but it's the army. It is the way of things. The army does a lot of things right, but I thought recognizing what they did wrong was just as important. Do what you have to do, but once you're out, don't take it with you.
 
Jarvy said:
I have seen guidelines set forth for firearms maintenance that are not only useless, but damaging to the weapons.
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I was making a query into your maintenance issues to which you feel were useless and damaging to weapons, which I find concerning. Although I am now retired after nearly 40 yrs combined service in Canada and Australia, I still consider myself a student of small arms.
 
I think what some people are ignoring is that there are 2 questions here, really.

1) Does the barrel itself require different treatment when first fired that makes a difference to how good the barrel will be - Lots of debate on this question

2) Does the GUN that just had a new barrel installed require any sort of special or different treatment, ie: "breaking in" while the parts are fitting themselves together and settling into a nice tight alignment. - This is where things like not running it too hot (ie: not firing 100 rds as fast as you can change the mags, not using hot hand-loads, using lots of lube, etc)

and actually a 3rd question:

3) After you take a gun apart, including a barrel change, what precautions should you take until you are sure everything is working correctly? - again, don't overheat, don't use really hot hand loads, lube well, no rapid fire, etc...

It's not just about the eventual accuracy of the barrel, it's also about safety and the long term reliability of the entire gun (hence the military procedures. Field stripping and cleaning after about 5 rds gives you a chance to see if anything is breaking or wearing in an unusual way or sticking or FTE or FTF etc etc...) NOT things you want to find out about in combat!!
 
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1feral1 said:
I was making a query into your maintenance issues to which you feel were useless and damaging to weapons, which I find concerning. Although I am now retired after nearly 40 yrs combined service in Canada and Australia, I still consider myself a student of small arms.
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The most horrific, which I was instructed to do by enough NCOs from enough different Regiments that I think it's fair to say that it's an institutional problem, was to use a sharp implement to scrape the surface at the bottom of a C7 flash hider until "the ring shines." (This was the common phrasing) This visible "ring" was of course the crown of the barrel.
 
Jarvy said:
The most horrific, which I was instructed to do by enough NCOs from enough different Regiments that I think it's fair to say that it's an institutional problem, was to use a sharp implement to scrape the surface at the bottom of a C7 flash hider until "the ring shines." (This was the common phrasing) This visible "ring" was of course the crown of the barrel.
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Sadly, that's piss poor leadership based on sheer ignorance, not written maintenance doctrine, and you won't find that information of 'ring shine' in the C7 pam. The C7 pam discourages ANY form of abrasive rubbing/scratching period. Also the CFTO pertaining to the C7 repair and maintenance does not reflect this either.

You will find some soldiers circumvent all they have properly learned, just to ##### over troops in some sort of power hungry rage. If I had an NCO try and pull that in my PL, he would be politely called aside and read the riot act.
 
1feral1 said:
Sadly, that's piss poor leadership based on sheer ignorance, not written maintenance doctrine, and you won't find that information of 'ring shine' in the C7 pam. The C7 pam discourages ANY form of abrasive rubbing/scratching period. Also the CFTO pertaining to the C7 repair and maintenance does not reflect this either.
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Nor do either have a break in procedure.
 
Would there be a difference in break-in requirements between a run of the mill target rifle, say a Remington 700 SPS and say, an Accuracy International rifle?
Would the Remington need it and the AI not?
 
I've done rebuilds on the AI AWF in 7.62mm, and AW50 AMR. On the 7.62mm version, new barrels came in ready to install, and were replaced after a mere 5000rds. It was a 'base' level of repair to replace the barrel, as it also had to have the serial number engraved on it. Once installed, the rifle was test fired from a jig @ 25m.

A detailed log book accompanies the rifle as part of CES (EIS), and follows the rifle throughout it's service life. If a Unit was deploying to the Ghan or Iraq, and the rifle had 4500rds logged, we'd replace the barrel. On the AWF and AW50, there was no running in. Once I left that facility and ended up in Field Force Units, rifles approaching 5000 rds would be called in and backloaded to base repair for their action.
 
I'm a believer in the "after the first shot, it's all downhill" school of thought. Make sure it's clean then start putting rounds through it.
 
phan108 said:
Just recently picked up my first AR, a brand new Bushmaster XM-15.
I been reading alot about a break in procedure.
I was wondeirng, if it is really necessary or just a myth?

Thanks
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TL;DR this entire god damn thread.

Simply put: No, there is no break in period for an AR-15.
 
So with a Chrome lined AR15 barrel there isn't a break in procedure at all. With good quality precision rifle barrels that are hand lapped by the manufacture like Bartlien, Hawk Hill, Proof Research, Brux, Benchmark etc there won't be either at the most you may have to smooth out the chamber since that isn't touched during the lapping procedure.

Now I'm sure what ever old sniper rifle you are talking about in your previous experience while in the service you probably weren't getting hand lapped barrels so you might have needed to do some break in to polish out all the burs and crap that were in the bore but as it stands now if you are breaking in a rifle with a good high quality match barrel YOU ARE HURTING YOUR BARREL.

This a video with some gentlemen who work at Bartlein who is pretty much the gold standard in precision barrels and they say that at most you might have to work some minor imperfections out of the chamber but because the barrel is hand lapped by them you don't need to do anything to the bore.
 
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