Bolt gun “break-in”

[longrange1]

Actually if i was a benchrest shooter, I go out and buy the best rifle, assembled from the best parts available, and by the best smith in the world...do a barrel break in because that is what benchies do, then point to my group size at 1000 yards as proof it works.... that is very definition of superstitious learning.

If on the other hand I buy 20 rifles, plan out a way to have them build as close to identical as is possible. then take 10 of them, use the exact same barrel break in procedure then record the results at 1000 yard. I am keeping this short, just assume from beginning to end as many variables are either eliminated or greatly minimized and actual shooting has humans 100% eliminated.

The other 10 rifles, no break in procedures, but everything else is as identical as possible. shoot at 1000 yards, record results.

NOW you have data to make your case one way or the other.

has anyone ever done anything like this? I have never, ever heard of such a test. have you?

until a test like that or something close is done, barrel break in is just a hypothesis backed by superstitious learning based on a series of "sample of one."

You might argue those samples of one provide a lot of convincing data, but i would argue they really don't. To many variables are left uncontrolled. AND most importantly... no method to account for the path not taken is factored in. IF you don't have anything to generate data points for the path you didn't take (break in if you don't, don't if you do a break in) how can you factually or statistically claim one choice or the other is actually working or better or does what you think it does.

There is compelling data that does suggest that the rifle's accuracy improves as the reamers nicks and burs smooth out. BUT NO ONE has compelling data that a formal break in procedure (not to mention which one) is actually THE way to achieve the improved results vs just letting it happen naturally. Why...because everyone points to a sample of one to back up their claim. Even if over the course of your life you own a 100 rifles and do a break in procedure on everyone, you only have 100 samples of 1. too many variables to make a factual claim. with that approach. And again, no data to compare against for having NOT broken in your barrel.

a real test would be time consuming and expensive. till then... you pay your money, takes your chances. you make a choice based on how it makes you feel, nothing more.

you are correct and no i do not know of any test...28-30 barrels for me and millions for rounds shot by the most accurate guns made and the guys building them trying to eliminate all the variables they can control is enough testing for me.

[1859sharps]

The BIG hole in the argument for barrel break in is the lack of a control for NOT breaking the barrel in. People believe it makes a difference, but no one KNOWS for sure that it does.

I have never, ever, ever read any argument or article in favor of break in that included control to compare for having not broken in the barrel. if such exists, I haven't seen it and no ever points to one if it does. without that, we are left with a "fact" that is based not on data, but superstitious learning.

even the compelling evidence that the smoothing out of the nicks and gouges from the reamer in the throat does not have the human element of learning eliminated to confirm that their elimination/reduction actually is the deciding factor in tighter groups. vs the shooter just getting to know the rifle better, improving their execution of the fundamentals etc.

[divingin]

I have never, ever, ever read any argument or article in favor of break in that included control to compare for having not broken in the barrel. if such exists, I haven't seen it and no ever points to one if it does.

It can't exist. Every barrel is different, even if cut from adjacent rods of steel on the same boring and rifling machines.

without that, we are left with a "fact" that is based not on data, but superstitious learning.

Yeah, it's known as Theoretical Science. You'll run into it every day, from theories about how stars and planets were formed to theories about human evolution to how salt affects your blood pressure. It's all based on theories, and not directly provable. The theories are put forward, and continuing evaluation either points more or less towards a likely conclusion. Some are right, some are wrong. That's the way it goes.

even the compelling evidence that the smoothing out of the nicks and gouges from the reamer in the throat does not have the human element of learning eliminated to confirm that their elimination/reduction actually is the deciding factor in tighter groups. vs the shooter just getting to know the rifle better, improving their execution of the fundamentals etc.

The fact that the evidence doesn't convince you that it applies doesn't mean it doesn't apply (nor does it mean it does.) But a lack of evidence towards one conclusion does not support the opposite conclusion.

In my case, I do believe in smoothing out the reamer marks - not so much to ensure accuracy (though if it does, great), but keep the copper fouling from getting out of hand during the first 25-50 rounds, when the rough throat tend to ablate a lot of jacket material and deposit it down the tube.

[Jesse 2]

I am getting a new barrel. If break-in steps are easy to follow, why not do it? Is the objective to remove carbon fouling in first shots? Removing copper at range would be a real hassle.

[LynnJr]

There are a ton of myths about removing copper that started years ago before the internet was fully up and running.
If you take a brake drum or a flywheel into a machine shop for turning they surface it hand it to you and you install it without issue.
If you put it in your house and install it a week later all is well.
If you toss it in the bed of your truck for a month it will turn into a rust bucket that will need surfacing before installation.
On chromoly rifle barrels if you use a strong ammonia based cleaner it will remove all the copper but it will also remove just about everything else inside the barrel leaving it squeaky clean.
If your a regular at the range this isn't a issue but if your a typical deer Hunter and put the gun away it is going to rust. The longer it sits naturally it gets worse and worse and will pit the barrel.

Today most shooters especially those frequenting internet gun forums have a wealth of knowledge at there fingertips so once they clean a bore they can oil it if the gun will sit for any length of time.
There are shooters on this forum myself included who use 28-30 % ammonia in there barrels to remove stubborn copper fouling without issue.
To use ammonia that potent you must use it outdoors so you don't cause any harm to yourself.
One poster put his gun in a 5 gallon bucket muzzle down and poured it down his barrel without doing anything else like patching or brushing and he posted pictures of the dark blue goo in the bucket.
Once done you clean your barrel like you would normally do and your all set.

[sfvshooter]

Just follow whatever directions your rifle came with. My MPA and HS Precision came with specific break-in procedures. Most others did not.

[sonofeugene]

I just clean it thoroughly and then coat everything with tungsten disulfide powder, including a few first rounds and the inside of the barrel, and go shoot.

[boattail]

There are two camps about break in on barrels. I have three custom barrels and one factory barrel that I fully intended on breaking in but forgot to bring my gear each time. Each gun got 50-60 rounds down the pipe before the first cleaning. Two of those three custom barrels have 5k each on them and still lay down 1/4" groups. The third barrel has only 5-700 rounds on it and doing well. The factory barrel put down it's best group the very first five shots down the tube. All four of these barrels are tack drivers and three of them see 4000 fps loads much of the time.

My advice for the general shooter is to clean after the first range trip and then clean when the accuracy drops off or 500 rounds or so if it goes that far. I have gone 800+ on my barrels a few times and never notice accuracy fall but cleaned them anyway.

I do high volume precision shooting with my guns and average 100+ rounds an hour when working them.

[longrange1]

There are two camps about break in on barrels. I have three custom barrels and one factory barrel that I fully intended on breaking in but forgot to bring my gear each time. Each gun got 50-60 rounds down the pipe before the first cleaning. Two of those three custom barrels have 5k each on them and still lay down 1/4" groups. The third barrel has only 5-700 rounds on it and doing well. The factory barrel put down it's best group the very first five shots down the tube. All four of these barrels are tack drivers and three of them see 4000 fps loads much of the time.

My advice for the general shooter is to clean after the first range trip and then clean when the accuracy drops off or 500 rounds or so if it goes that far. I have gone 800+ on my barrels a few times and never notice accuracy fall but cleaned them anyway.

I do high volume precision shooting with my guns and average 100+ rounds an hour when working them.

so your saying you have 2 guns with 5000 rounds through each of them that you shoot at 4000FPS and they still shoot 1/4" groups?

[The War Wagon]

My break-in procedure for a new rifle is to shoot a bunch through and then go clean it.

3 shots with no malfunctions. Broken in.

[LynnJr]

so your saying you have 2 guns with 5000 rounds through each of them that you shoot at 4000FPS and they still shoot 1/4" groups?

Don't feed the obvious trolls

[ar15barrels]

so your saying you have 2 guns with 5000 rounds through each of them that you shoot at 4000FPS and they still shoot 1/4" groups?

...at 25yds.
He shoots 10 rounds and picks the best 5 as his "group".

[boattail]

so your saying you have 2 guns with 5000 rounds through each of them that you shoot at 4000FPS and they still shoot 1/4" groups?

Yes, I have three Black Hole Weaponry ar15 barrels and two of them have 5000 rounds on them. My loads are 3800 fps to 4100 fps out of 24" tubes.

I do fully expect these barrels to die a rapid death one of these days but for now they still have it. These are chambered in 20 Practical.

Here is one barrel's target shot with rounds 2891-2895

[boattail]

...at 25yds.
He shoots 10 rounds and picks the best 5 as his "group".

So that is how it's done.....

[ar15barrels]

two of them have 5000 rounds on them.
Here is one barrel's target shot with rounds 2891-2895

So what you mean is two of them have 5000 rounds COMBINED.
That's around 2500 each.
That's why you are showing a group at around 2900 rounds.
Show us 5 more groups on the same piece of target paper so we know you are not trying to pass off one hand-picked group as "average".