Barrel break in

ajarmst said:
There is a fairly good article from the "don't break in" camp at http://www.6mmbr.com/gailmcmbreakin.html



I agree that it is not only a waste of time, but wears your barrel more quickly. I find the same with custom barrel manufactures that void your warranty if you use moly. They have a vested interest in not making a barrel last longer - the shooter buys fewer barrels. I believe that cleaning rods are more detrimental to the bore than most anything else you can do to them - I managed to destroy the bore of a Coey 22 in my youth due to cleaning rod wear.

If the borescope shows rough machine marks in the throat, which it very often does, scrubing this area (only) with JB Bore Paste smooths the rough edges quickly. A poorly finished factory barrel can also benefit from a JB Paste treatment, but I limit this as much as possible.

My 6BR shooting clean burning VV powder and moly bullets sees a cleaning rod every 300 or so rounds. The first few groups open up after cleaning.

My next few barrels will be hammer forged units from Lothar Walther.
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Barrel Break in

Chamber reamers leave marks in the barrel leade that will scape jacket material and spray copper down the bore. That should be cleaned to prevent a build-up. A few shots will smooth the leade rifling. A bore scope will reveal tooling marks. Other than that issue your new barrel is ready to shoot. Enjoy it.

Barrel chambers by custom gunsmiths are of much better quality than factory rifles and arrive ready for load development.
 
OKTREE said:
If the borescope shows rough machine marks in the throat, which it very often does, scrubing this area (only) with JB Bore Paste smooths the rough edges quickly. A poorly finished factory barrel can also benefit from a JB Paste treatment, but I limit this as much as possible.
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Does JB make a lapping bore paste that you are referring to?

I have not found the JB Bore cleaning paste abrasive to steel. It removes fouling very well though. Try rubbing it on a piece of barrel for an hour or two with a patch and you won't measure any difference in dimension.... not even a ten thou...
 
Ron AKA said:
Actually I don't think much study is needed on break in. Everyone that does it can do their own study. You just have to check and see how many patches it takes to remove all the copper (white patch, no blue). All barrels are going to be different based on how well finished the bore surface is. Hand lapped custom barrels that have not been over polished will clean up the fastest -- as little as two or three shots. Rough factory non lapped barrels will clean up the slowest, and some will never clean up. Of the latter you may as well just shoot them.

So "break-in" needs to be barrel specific. Get a good ammonia based cleaner like Barnes CR-10, and let the colour of the patches tell you when the barrel is broken in. It might be one or two shots, or never! I suspect that is why there is controversy about the subject. It is not a one size fits all process.
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I hate beating this one to death because it really is a no-win argument. Ron's posts show he is intelligent, and I really enjoy his posts, so I really want to emphasize this is not a slight against him.

First, Define barrel Break-In? The end-point of the exercise would appear to be a barrel that goes for the longest period of time before it starts to show copper fouling. If you really believe that a few chunks of rags and some amonmia applied to 416 stainless steel is going to influence the degree of wear over the space of 20, 30 or 50 shots, I think that is hopelessly ldealistic.

When you have a clear definition of "Break In" you have the basis for a hypothesis that can undergo proper quantitative - not qualitative - controlled and repeatable study.

The only way that can be done properly is to fire identical loads, with identical bullets to identical dimensions in identical barrels, reamed and chambered to identical dimensions under identical conditions. Unless you have access to a small sampling of oh, 20 or more barrels from one manufacturer, followed by 20 more from another, and another, with samlings from EDM, CnC, Cut Riflers, Button Riflers, Hammer Forgers, and broachers that all meet the above criteria. Then you need to reverse engineer the process taking precise measuements and microscopic analysis of the results, and incorporating the terminal ballistic effects.

Then, someone else needs to do exactly the same thing to validate the findings. I also know that in spite of overwhelming evidence, people still practice the contrary. There are still people in the 21st Century that really believe that human rhinoviruses have an affinity for sub-zero dead air, and one can contract these viruses by simple exposure to this air, and that layers of wool protect you from these viruses..... (take some Buckley's)

As someone that sells barrels, it would be in my commericial interest to promote something that causes people to buy replacement barrels more often. "Go forth and break-in your 264 Win Mag and don't stop until your patches turn purple". I cannot and will not.

That is not to say that there is not some benefit to the process, but curiously, nobody has ever properly studied the results. One would have thought that barrel manufacturers have a great deal to gain by doing so, but alas, they have not. As it stands some promote it, some do not. Some esteemed gunmsmiths promote it and some do not.

Understand that if you decide to practice break-in, you are only doing so to satisfy your own beliefs.
 
Funny how Barrel dealers agree on this - barrel break in is a waste of time.

What are you trying to break in?

if the bore is properly lapped and smooth, shooting will only make it rougher.

If there is pits in the barrel where copper can collect, that's nice and will fill in with some shooting.

If the bore can foul enough that accuracy degrades after X number of shots, then clean enough so accuracy is returned and clean before accuracy drops off.

Only one barrel that needed to be cleaned by 20rds - bullets blew up other wise. have another that I have stopped counting when I passed 200rds.

Light amounts of copper does not affect the final accuracy of the barrel. All barrels will copper foul at some point in their lifespan.

I have never seen a modern barrel shooting modern ammo CLOG UP with fouling.

ETC, etc, etc.

if it makes you feel better to break in, go for it.

I just put on a new Shilen Select Match barrel in 223 for my F TR rig. My procedure went as follows.

Clean the bore well to get rid of any oils and dirt
Bore sight by actually looking down the bore. 1 shot at 60yds. Adjust scope, 2nd shot at 60yds close enough. Reset for 100yds - too cold and windy to go to 200yds.

Start load testing....

Found one node 9 shots later at a powder amount that I suspected would be decent.
Shot more to find pressure peak but never reached it - but it is cold.

26rds fired and I have a node to play with and need more shots to find the upper limits.

I may clean the barrel next outing before shooting just out of curiosity.

YMMV.

Jerry
 
There are two kinds of bore fouling... powder and copper... Kreiger and Lilja have definite thoughts of the effects vaporized copper fouling the bore of a new barrel... until the freshly cut throat is broken in... both very intelligent, experienced highly qualified barrel makers. They write about fouling on their websites. Interesting reading.
 
Just some theoretical musing, that happens to fit my experience with what happens in real life... Years ago, I was very surprised to learn that when you hand lapped something, you do not use a hard material to lap a hard material. What you do is use a softer material to hold some abrasive compound, and the abrasive compound grinds down the hard material. This not only applies when you hand lap in a machine shop. Custom barrels are hand lapped by pouring some lead into the barrel to make a close fitting plug. The plug is embedded with abrasive material, and then hand stroked up and down the barrel to polish it to a specific surface finish. If you go too smooth that is bad, and the copper jackets can gall onto the surface. If you leave it too rough, then the rough surface provides abrasion to grind copper off the bullets.

So what does that have to do with break in? I would suggest if you get a barrel that has been overlapped then you are toast. You can't really break it in, and you need to be talking to the custom barrel maker about getting a replacement barrel. If it is too rough, and that is likely to be the case with a factory barrel, then the copper fills in the rough voids, and starts to act like the lapping block. The sharp steel peaks abrade away the copper jacketed bullets. The steel peaks are protected by the copper in the voids (just like a soft lap or lead plug. All you do is wear down the bullets, and that accomplishes nothing. The fix is to get rid of the copper out of the voids and low spots. That lets the bullets round over and smooth down the high spots if they are not too big.

Since the steel high spots are protecting the copper, the best way to get the copper out is chemically (ammonia). Once the copper is out of the way, you can get back to smoothing down the high steel spots. You either win at this and the copper filling stops, or the peaks are too high and you have a copper fouler for life, unless you try something harsh like fire lapping.

So, I remain unconvinced by the break-in is a waste of time argument. Yes, for bad barrels it probably is. And for the perfect custom barrel it probably is too. But for many barrels you can smooth them down by removing the copper after each of the initial shots and breaking up the "soft lap effect". And the secret of this is to use an ammonia cleaner that will tell you pretty quickly what kind of barrel you have to deal with.
 
Obtunded said:
If you really believe that a few chunks of rags and some amonmia applied to 416 stainless steel is going to influence the degree of wear over the space of 20, 30 or 50 shots, I think that is hopelessly ldealistic.
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a bunch of years ago I was in Machias WA shooting a cross-the-course match, and a well known Tacoma gunsmith (and High-Master shooter) delivered a freshly built rifle to a competitor. We were all admiring the rifle and the owner voiced concern over shooting the rifle at the match, rather than using his #2 rifle that day and breaking the new one in properly.

The gunsmith told him something to the effect of; "if you follow a strict 50 shot clean and shoot break-in procedure, you should get a useful barrel life of 5000 rounds or so, if you don't do a strict 50 shot break in procedure, you should get a useful barrel life of 5050 rounds or so.
 
If it's a high end target gun... I'd go with the Savage procedure. Good as any.

Otherwise, I just shoot about 25 rounds strings, then clean to get about 200 rounds through as this is when I find the gun settles into it's "groove" (none are "rapid fire"). Both my Tavor and my XCR (6.8) both improved accuracy vastly after 200 rounds.

It somewhat depends on the round too. My R93 in .257 bee does not get 5 round hot strings put through it. The barrel cooks after 3. That being said, I wouldn't hold back firing more if I was hunting and had too. Course, all the deer I've shot with it drop in a heap.... so I haven't had to.
 
guntech said:
There are two kinds of bore fouling... powder and copper... Kreiger and Lilja have definite thoughts of the effects vaporized copper fouling the bore of a new barrel... until the freshly cut throat is broken in... both very intelligent, experienced highly qualified barrel makers. They write about fouling on their websites. Interesting reading.
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Border Barrels also echo's this concern... http://www.border-barrels.com/articles/shoot-in.htm

I certainly take notice when 3 of the best makers in the world recommend shooting-in your freshly cut chamber.
 
Ron AKA said:
Just some theoretical musing, that happens to fit So what does that have to do with break in? I would suggest if you get a barrel that has been overlapped then you are toast.

...

But for many barrels you can smooth them down by removing the copper after each of the initial shots and breaking up the "soft lap effect". And the secret of this is to use an ammonia cleaner that will tell you pretty quickly what kind of barrel you have to deal with.
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You're sort of arguing against yourself there. (1) What is this "soft lap effect"? If it's lapping, what is the abrasive being used? (2) You claim (correctly, in my opinion) that over-lapping is bad. But if shooting the rifle during break-in is "lapping", then it's also lapping when you're shooting for effect. Which, by your logic, could lead to over-lapping -- which implies that the extra rounds you shoot decrease the life of the barrell.

I'll start breaking in when I see real evidence (as in, real measurements of real rifles along with controls) that break-in either lengthens the lifespan of the barrell or improves its accuracy enough for a shortened lifespan to be worth it.

Even if it's someone I greatly respect (as many who argue for break-in are), I still need to see something other than a vague theory that somehow shooting bullets down a barrel polishes it.
 
bcode said:
Border Barrels also echo's this concern... http://www.border-barrels.com/articles/shoot-in.htm

I certainly take notice when 3 of the best makers in the world recommend shooting-in your freshly cut chamber.
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These guys talk about having 'dirt' in your barrel and also recommend cleaning from the muzzle.
 
badly copper fouled barrel.... and the cure

well folks here's a story to open your eyes. A few years ago, I took my chronograph to the range in Campbell River, bc, (thats on the island) to clock some loads for a buddy's 270. We got set up and settled in for some numbers. He had loaded enough H4831 in behind a 140gr. bullet to give a speed around 2850-2900 according to the Hornady manual, and @2 grains under max. OK first shot was a tremendous blast and footlong fireball, ringing ears (with muffs) and a speed of 3175. wow! "does the bolts open?"
Yup, no problem! So 8 or 10 more went downrange, with the now slightly dirty barrel getting faster, into the 3250 fps range! Accuracy was minute
of target, about 8 inches at 100yd.
I persuaded him to give me that thing to take home and give it a good cleaning with the electronic machine. It took me two days of running the electric, draining, swabbing, brushing, refilling and running again, to get that thing clean of copper. A few passes with sweets made sure there was no blue on a patch. Then it went to the world renowned Nobby uno of Courtenay, for a bedding job. (he is now retired and does not work on guns anymore so don't call.) Back to the range after all that, and presto, the exact same loads went 350-400fps SLOWER, with a nice soft 'boom', and ole betsy shot like a tack. My friend was actually a bit disappointed with the speed, but hey thats what a 270 should do. Ok go up a grain if you must.

Moral of the story... don't just assume that a quick patch and brush with hoppes after a hunting trip is good enough. This condition took many years to build up, but advances real fast once the copper gets a good hold in the pipe. I am guessing the bore was several thou. smaller than .277.

So the outcome was a happy one, and nobody lost an eye with a blown up gun, or worse. Cheers everybody, I hope this may be a learning experience for a few frustrated shooters out there.
 
Mike G, you have generated a lot of discussion. However, you have not told use what kind of barrel you have. Is it a factory gun, and if so what one? Or, is it a custom hand lapped barrel? and again by who?
 
Cleaned the barrel - no copper

Shot another 36rds and cleaned again. As the pressure of the load rose, the powder fouling dropped off as is common with modern powders.

Cleaned again, took 1/2 as many patches to get rid of the powder - again, no copper.

I use a very strong ammonia solvent so if there is copper, it will show up.

YMMV.

Jerry
 
Ron AKA said:
Mike G, you have generated a lot of discussion. However, you have not told use what kind of barrel you have. Is it a factory gun, and if so what one? Or, is it a custom hand lapped barrel? and again by who?
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It's a factory 700p 338 LM. I will be rebarreling to a 338 LM AI in the near future. I have not loaded any for it yet. The post your loading bench thread got me to rethink my bench it been a weekend of rebuilding. It should be finished tomorrow. And I can get loading. I appreciate all the responses and opinions. It's only my second NEW riffle all others have been new to me. Just want to make sure I'm doing things right......
 
Always remember that centrefire target / varmint, centrefire hunting, rimfire recreational, rimfire target and .22 magnum shooters all have different approaches based on the firearm, ammunition and purpose they face which can make for significant diferences in how you would approach barrel break in.
 
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