Do All Rifles Need Break In

I am always surprised at the blind faith behind the many opinions surrounding barrel break-in in the face of tangible physics....

Copper fouling is measured in molecules of thickness. Sliding wear is not influenced greatly by a few molecules of copper. Any structural changes that are going to occur are the result of the tremendous heat generated by a combination of friction, pressure and combustion converting steel to plasma. That is almost always confined to the first couple of inches beyond the throat as pressure and temperature dissipate. The surface area of any imperfections will be dramatically altered with the very first shot - before any fouling has ever occurred.

The steel that people purport to "break-in" is vaporized after several shots anyway.

There are no shortage of opinions on this subject and even the barrel makers themselves have wildly differing views of how it should be done - if at all.

I reiterate, until someone can produce abstracts of credible, quantified, controlled multi-center research on the science and the benefits of Barrel break-in, it remains lore with as many potential down-sides as up-sides, but above all do what you like... it's YOUR barrel.


Slopping a few cleaning patches with copper solvent is not going to appreciably change the structural re-contouring that occurs as part of the inevitable throat erosion process.
 
My own uneducated thoughts on this are........

The barrel will be dirty when you get a new rifle. Maybe a few "test" shots at the factory. Maybe some crumbs (metal filings) in barrel.

Wipe out the crumbs so they don't score or scratch the barrel. Before first shot fired. You may find that some of the patch will hang up on bad spots. May show by looking down barrel after the one patch dragged through.

Fire a shot. Wipe out. Fire a shot. Wipe out. For a few cycles.
 
Max Owner said:
My own uneducated thoughts on this are........

The barrel will be dirty when you get a new rifle. Maybe a few "test" shots at the factory. Maybe some crumbs (metal filings) in barrel.

Wipe out the crumbs so they don't score or scratch the barrel. Before first shot fired. You may find that some of the patch will hang up on bad spots. May show by looking down barrel after the one patch dragged through.

Fire a shot. Wipe out. Fire a shot. Wipe out. For a few cycles.
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Excellent thoughts! Especially with the un-lapped barrels preferred by some of the Canadian barrel makers.
 
I would put it this way. No one has to so call break-in barrel, but it doesn't hurt a shooter or the rifle. That you tube clip is a red neck crap.
For me breaking time is a time to reflect on few things, like sighting in, initial load development, getting to know the rifle, checking all screws if they tight and so on.
I do break it in, usually 12-15 shots and clean it after ward.

Good Luck
 
redman said:
Boomer, this is the only part I'm having trouble with regarding the explanation you are quoting. Although I'm an engineer, I'm not a metallurgial one, but know some basics in the latter regard. That having been said, the only articles on hardening steel using heat I found involved heating the steel at temperatures between 500 and 1000ºC for several hours if not days. A good example of such articles comes from this site. I doubt that the ridge (which I tend to believe might actually exist on some rifles) would have such high temperatures maintained for so long over the course of a typical shooting session (which, if you're me, involves breaks to eat, change targets, chat with range buddy, etc. thus allowing the barrel to cool).

Just a thought.
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Explosive hardening is used to enhance long wearing characteristics in surfaces subject to high impact or high abrasion; for example austenitic manganese steel used in crusher jaws, grinding mills, and railway frogs. While no shock wave occurs in a propellant explosion, it is possible that the BHN of the metal subjected to the heat and pressure over a number of firings could be effected. Naturally the exposure time to a shock wave in the case of explosive hardening or in the case of exposure to the heat and pressure exerted on a steel surface by a propellant explosion is measured in milliseconds.
 
PeterPan said:
Jason,
why then Krieger, Lilja recommend barrel break-in?
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Why to sell you another barrel of course :rolleyes::dancingbanana::dancingbanana: because most shooters do not know how to properly clean there barrels thus most barrels wear out prematurely due in part of damage caused by cleaning .It is a myth about Barrel break in maybe 20 yrs ago but with today's Steels and Alloys and improvements in tool bits this is a marketing ploy by the manufacturer's
 
Boomer said:
Explosive hardening is used to enhance long wearing characteristics in surfaces subject to high impact or high abrasion; for example austenitic manganese steel used in crusher jaws, grinding mills, and railway frogs. While no shock wave occurs in a propellant explosion, it is possible that the BHN of the metal subjected to the heat and pressure over a number of firings could be effected. Naturally the exposure time to a shock wave in the case of explosive hardening or in the case of exposure to the heat and pressure exerted on a steel surface by a propellant explosion is measured in milliseconds.
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Hi Boomer,

I think we're really getting beyond my basic structural engineering/chemistry knowledge, but I will say that I found this: of the research abstracts, patents and corporate marketing material I found related to explosive hardening, all pertained to only manganese steel alloys. On top of that, from what I found, the pressures used were 70 to 80 kilobar, or 7000 to 8000 MPa, whereas the max pressure from a .308 Win. is about 20 times less.

I don't know what rifle manufacturers use, but my rifle's barrel is made of a chome-molybdenum-nickel alloy (no manganese that I know of), so my skepticism of this process remains.

Then again, I'll echo the notions of some in saying that I'd love to see some experiments with this, since I doubt that this armchair theorizing will amount to much! :redface:
 
Savage said:
Why to sell you another barrel of course :rolleyes::dancingbanana::dancingbanana: because most shooters do not know how to properly clean there barrels thus most barrels wear out prematurely due in part of damage caused by cleaning .It is a myth about Barrel break in maybe 20 yrs ago but with today's Steels and Alloys and improvements in tool bits this is a marketing ploy by the manufacturer's
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Savage,
those shooters who don't know how to clean the barrel are not shooting 1/2MOA groups ol day long to start with. And barrel wearing out prematurely due in part by cleaning, COMMON :) :) What kind of brushes we talking here?? steel RC 55??? :)
Breaking in my opinion is done by most of the shooters who compete, and maybe is not necessary, but it doesn't hurt rifle and there are many articles supporting that myth.

Greetings ;)
 
PeterPan said:
Savage,
those shooters who don't know how to clean the barrel are not shooting 1/2MOA groups ol day long to start with. And barrel wearing out prematurely due in part by cleaning, COMMON :) :) What kind of brushes we talking here?? steel RC 55??? :)
Breaking in my opinion is done by most of the shooters who compete, and maybe is not necessary, but it doesn't hurt rifle and there are many articles supporting that myth.

Greetings ;)
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Well I just recieved my target rifle that I ordered from McMillan rifles I asked about barrel Break in the response from Rock McMillan was you dont have to just shoot it.
 
AR (Abrasion Resistant) steels are used commonly in my trade and actually become harder with exposure to friction. Yes, these types of steels contain Manganese, and I am not the metallurgist we need to make the jump here to barrel alloys.

Besides, I'm currently poor, all my rifles are broken in by someone who can afford new rifles!

A rifle which shoots 1 MOA out of the box might not get better due to the barrel break in (or lack of), but it may be made better through the trigger and also by load development.
 
redman said:
Hi Boomer,

I think we're really getting beyond my basic structural engineering/chemistry knowledge, but I will say that I found this: of the research abstracts, patents and corporate marketing material I found related to explosive hardening, all pertained to only manganese steel alloys. On top of that, from what I found, the pressures used were 70 to 80 kilobar, or 7000 to 8000 MPa, whereas the max pressure from a .308 Win. is about 20 times less.

I don't know what rifle manufacturers use, but my rifle's barrel is made of a chome-molybdenum-nickel alloy (no manganese that I know of), so my skepticism of this process remains.

Then again, I'll echo the notions of some in saying that I'd love to see some experiments with this, since I doubt that this armchair theorizing will amount to much! :redface:
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I would have thought that Jack Krieger's experience, and observations might count for something in this regard. I have read a fair bit of Kreiger's published observations and opinions, and given the man's experience I wouldn't discount it out of hand. It could actually be considered a scientific evaluation as he has the facilities to conduct testing with very tight controls in place. When he comes forward with an opinion, it is the result of observing a trend which has repeated in hundreds of tests, rather than a handful. Another related subject which he has talked about at some length is de-stressing barrel steel, the causes of stress, and how it relates to accuracy.

With respect to steel, generally what applies in one case will also apply in another. Manganese has special properties due to a high carbon content and lack of other alloys which make it particularly resistant to abrasion. But manganese is steel and subject to the same reactions to stress as other steels, which includes work hardening. That was the point I was trying to make with respect to barrel steel alloys, be they CM or SS. Explosive hardening in the case of manganese is work hardening, and the explosion of propellant gasses on a "softer" steel, such as barrel steel, would also create a work hardened surface. A very small burr, or ridge left by a chamber reamer which cuts across the lay of the steel, when subject to repeated firings will almost certainly become harder and more wear resistant.
 
I have just had the pleasure of inspecting two barrels that are worn from shooting. Both are 6.5 Mystics that I was using for F class.

If there is any work hardening of the steel, no one told that to the rifling.

The first barrel has seen upwards of 1800rds and has NO rifling 2" in front of the chamber. The second shot about 1500rds has none about 1" in front of the chamber.

Wear is wear and firing bullets simply removes important bits of steel.

If work hardening did occur, I would be able to shoot my barrels for much longer. Unfortunately, it didn't.

So my thoughts on barrel break in remain, I don't bother.

Jerry
 
Hi Jerry,

Although I'm also skeptical (I chose not to break mine in), I believe boomer made no reference to effects on rifling. Instead, he points to the reaming edge at the end of the chamber that gets hardened, stripping bits of jacketing, therefore increasing fouling.

Any thoughts on that?

mysticplayer said:
I have just had the pleasure of inspecting two barrels that are worn from shooting. Both are 6.5 Mystics that I was using for F class.

If there is any work hardening of the steel, no one told that to the rifling.

The first barrel has seen upwards of 1800rds and has NO rifling 2" in front of the chamber. The second shot about 1500rds has none about 1" in front of the chamber.

Wear is wear and firing bullets simply removes important bits of steel.

If work hardening did occur, I would be able to shoot my barrels for much longer. Unfortunately, it didn't.

So my thoughts on barrel break in remain, I don't bother.

Jerry
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As I said, any issues with the orig throat from chambering are now 1 to 2" downstream :)

Normal firing of the rifle will dissolve any orig rough spots in the throat and likely cause more rough spots elsewhere in the pipe.

doesn't take more then 50rds of normal firing. Big reason why copper fouling tends to dissappear after the 'break in' of 50 or so rds. That's just throat erosion.

However, copper fouling may start to reappear later on in the barrels life cycle. That is bore erosion and really isn't a big deal. Just gives you an idea that your barrel is heading into the back half of its life.

So unless there is a serious chip/edge sticking INTO the path of the bullet, it really doesn't matter. Pitting and 'gator skin' will fill with fouling and the bullet will ride over this quite nicely.

Having the rifling wear away though cannot be fixed by cleaning or voodoo procedures.

Jerry
 
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