Barrel Break-in... show me the money

[chino1969]

I have no problem with breaking in a barrel, I just don't understand how copper, or bronze, can wear down stainless steel.
After my experience with a Krieger I don't think I'll ever own a factory barrel again. My Weatherby is being rebarelled right now. My 284 is next.

Twud,
You have crossed over the line and here are a few tips to keep you rooted in reality. My first custom barrel almost ruined me because I was introduced to an accuracy level I never dreamed possible. The problem was when I went back to shooting my factory rifles I was dismally disappointed. You have to be able to separate the potential of a custom barrel versus a factory barrel. I conciously force myself to periodically shoot my factory rigs to keep from getting totally spoiled. There's nothing wrong with that but you'll find that it's not cheap. If you are that close to Clarence, you'll find yourself coming up with other projects you would like him to put together for you.
As I've said on other threads, a good gunsmith is like a good tailor. Once you take the time to establish a rapport, get a feel for him, and he gets a feel for you, you'll have a custom rig that meets your expectations. The problem is you'll want more. I know because I've been bitten.

Lou Baccino
Chino69

 

[fdshuster]

Lou: Well said. I'm about to drive to my 'smith now to give him his Christmas present. He has done outstanding work, rebarreling 3 of my rifles, plus other work, and a re-barrel job for my son. When you give a simple "thank you", you have made a friend for life, since, mostly, all the feedback they get is negative,'bitchen complaints.

 

[chino1969]

Lou: Well said. I'm about to drive to my 'smith now to give him his Christmas present. He has done outstanding work, rebarreling 3 of my rifles, plus other work, and a re-barrel job for my son. When you give a simple "thank you", you have made a friend for life, since, mostly, all the feedback they get is negative,'bitchen complaints.

I agree. You'll get the best performance if you give the man positive feedback. I get a kick out of people who go to a renowned smith and try to tell him how to do his job; it would tick anybody off that is renowned in their field. This is not to be confused with doing your homework, being able to convey your needs, being accurate and specific in what you want. A little humility, on the gunowner's part, goes a long way in developing a good working relationship.

Lou Baccino
Chino69

 

[Twud]

I have 4 rifles that I shoot and hunt with. A 22-250, a 257 Wby, a 6 BR and a 284. These are my work horses, the ones that I want to shoot well. The others shoot OK, and that's fine. It's such a thrill to have your first group shoot one hole, especially when you've struggled with it for years. Although this is is unnecessary for hunting purposes, it gives me a psychological boost of confidence.
And I can afford it.

 

[jo191145]

Twud, wouldn't it be the bullet forced out the barrel repeatedly that would work on smoothing out the irregularitys.
All the solvent and brass brush does is remove the copper fouling,and carbon) left in the barrel after the bullet wears on the irregularity.
I'll go a little deeper. As a bullet passes,under duress)
past a burr, a little of the burr will be worn down and in the
process a little copper from the jacket will be shaved off by
the burr and will build up in front of the burr. A scrubbing
with solvent and a brass brush will take out the copper build
up but do practicality nothing to smooth out the burr. With
the copper removed from the burr the next round forced out the barrel will wear down the burr more than it would if the burr
was protected by the copper fouling from the previous shot.
Look down a good custom barrel with a bore scope and there
should be essentially no burrs or imperfections. Look down a
factory barrel and it will be riddled with tiny,mostly),hopefully)
imperfections. Thats why barrel break in on a factory rifle,
if you want to make it as accurate as is reasonable, is necessary. On a good custom barrel, without a lot of imperfections, benifits from a break-in regimen may be minimal
or nonexistent. For the bench shooter out to win a trophy, even
minimal improvement before that first shoot may be worth it.
If you want the best accuracy from your barrel, yes, break-in is
benificial. If the gun is shooting good enough to suit you right
out of the box and you don't care to spend the time to make it shoot any better, then break-in for you is a waste of time. There really is nothing scientific about this, it's just sort of common sense and whatever purpose or expectation an individual has for thier gun. Testimony from a lot of shooters
is that their gun shot best after 50 to 300 rounds,depending on
the individual gun. This is due to the barrel getting "broken-in". If fractions of a MOA is important to you then you can speed this process up by following a good break-in procedure.
If it's not important to you then why waste your time. But what
ever you do, have fun doing it.
God bless America,and please hurry)

Here in entirety is the answer to the question. No scientific studies needed. As the poster stated just common sense.
I do not break in my custom handlapped tubes. Factory tubes are quite different. I break these in with my own method that does not include frequent cleaning or abrasives. Seems to work very well.

 

[chino1969]

Here's a method I use to break in new factory or non custom barrels. I just bought a brand new Adams & Bennett barrel from Midway. I examined the bore with a borescope and it was typical of many non custom aftermarket barrels; rough with tooling marks. The lands and grooves, however, were consistent and actually pretty good. I thourougly cleaned the bore and then lapped it with 400 grit silicon carbide. I used the VFG cleaning felts that Brownell's sells. For those unfamiliar, these are cylindrical felts that screw onto a jag. The felt is able to follow the id of the bore and you can snug it up by tightening your cleaning rod which forces the felt further down the jag. The felts are available in different calibers. After lapping the bore, I then used a pointed Foredom buffing felt that had an ogive closely matching a bullet. I had to trim a little off the od of the felt by using an Xacto knife while the Foredom handpiece was held in a vice; a rudimentary lathe of sorts. Using red rouge polishing compound, I polished the throat area. I cleaned the bore thoroughly and checked with the borescope and it was improved considerably. The tooling marks from the reamer were smoothed out, the transition from the throat to the bore was smooth, and the lands and grooves had many of the rough spots smoothed out. Bear in mind this is only a $125.00 pre-fit barrel but I did this to experiment and do my own testing. The barrel will just be shot, no break in of any kind. It will receive a cleaning after every 30 rds. If it shoots fairly accurately, it may make a decent live varmint barrel.

I have plenty of custom barrels that are deadly accurate. I clean after every 20 rds. but no longer perform the tedious break in process we've been discussing. This is just another experiment, not laboratory or clinical grade, just to prove a theory to myself. If a $125.00 pre-fit barrel can be made to shoot consistently accurate I can shoot much more and not worry about shooting my barrel out.

Lou Baccino
Chino69

 

[Akbushape]

Chino69, "the barrel will just be shot and no break-in done".??
With the hand lapping, you have already done a major portion
of the break-in. The remainder of the break-in will be done in the first 50 to perhaps as much as 300 rounds fired through the
gun. It is going to go through "break-in" one way or another,
just as sure as i'm setting here. It has to happen. It can be done the slow way or it can be speeded up by using a standard break-in procedure. By just shooting it you can eventually accomplish break-in but it will take longer. Accuracy will improve with your barrel until it reaches it's full potential at X number of rounds. It will happen whether we call it that or not.
if it looks like a duck, quacks like a duck, walks like a duck.....

 

[chino1969]

Chino69, "the barrel will just be shot and no break-in done".??
With the hand lapping, you have already done a major portion
of the break-in. The remainder of the break-in will be done in the first 50 to perhaps as much as 300 rounds fired through the
gun. It is going to go through "break-in" one way or another,
just as sure as i'm setting here. It has to happen. It can be done the slow way or it can be speeded up by using a standard break-in procedure. By just shooting it you can eventually accomplish break-in but it will take longer. Accuracy will improve with your barrel until it reaches it's full potential at X number of rounds. It will happen whether we call it that or not.
if it looks like a duck, quacks like a duck, walks like a duck.....

I agree with everything you just said. I stopped breaking in my custom barrels a few barrels ago because I feel it's a waste of time and, as you said, it will be broken in after 'X' amount of rounds either way. I closely monitored brand new custom barrels with a bore scope and see no advantages to the tedious one shot, clean method traditionally used for break in.

This cheap barrel I have is going to be an experiment. You are right in stating I've broken it in partially by lapping. I'm curious to see if just shooting it will yield similar results I've obtained with the custom barrels.

Lou Baccino
Chino69

 

[Twud]

No one has yet addressed my question. How can copper, a very soft metal, ever wear down stainless or CM steel? I like some of the ideas and I think something like JB might work, but not bronze or solvent.

 

[jo191145]

Twud
Ever see water wear down a rock?
Friction causes wear in everything I can think of offhand on a Friday night if you get my drift.

Simply speaking an unlapped bore will be slightly rough. The key to smoothing it up quickly is to pass bullets through it without any copper already present in the bore. Or lap it.

Copper jacketing will sheer off on the rough spots of a bore. It will tend not to collect on the smoother sections of the bore.
What happens with repeated firing with accumulated copper present is this. The copper fouling will fill in the rough spots in effect covering them over. No wear/smoothing will take place in the rough sections that require it the most. the bullet will be riding on copper.

At the same time the smooth sections of the barrel will be undergoing wear caused by the bullet.
So the rough remains rough and potentially a smaller diameter as the smooth wears itself away.
It might be fair to say peening over the rough spots is a more apt description than wearing them smooth.
Every barrel is different and requires some expierience with copper fouling to diagnose IMHO.
Most decent handlapped tubes require little more than 10-20 rds then clean thoroughly and they're ready to go.

Factory or old pitted milsurp barrels are an entirely different story.
So far I have yet to see a barrel that exhibited more consistent accuracy with a copper clad bore as opposed to one that collected none.
I have seen factory barrels that would go haywire as soon as the copper fouling reached the crown. Some might claim the crown was at fault but as long as the copper was under control and not reaching the crown those barrels shot darn well.

 

[Twud]

Now that makes some sense. You got me with the water part.

 

[favload]

Guys, don't forget that water wears down mountains mostly due to the suspended load,hard minerals like quartz) that it transports over softer material as it moves over it. Like a water jet using garnet grit to cut steel. It's really not the water alone doing most of the work. That said when you rub your finger over a diamond,or a rifle trigger)you too can remove material on the atomic level. After a few billion years you may see a result. I am willing to bet that hard carbon residue formed from the heat and pressure of the firing process from powder burn along with impurities in the copper itself as well as metal from your barrel all weather and erode the tube as much as anything else.

 

[Akbushape]

Wrap a cotton string around a steel pipe and saw it back and forth for a while and you can polish a ring around the pipe. The
item doing the polishing doesn't have to be harder than the
material being polished. It just takes repetitive motion. The
greater the pressure the greater the friction which causes the
erosion. Barring all other contributing factors like heat from
the powder exploding and the carbon from the burned powder, if
you slam a copper jacketed bullet through a stainless steel barrel at 3000 fps it will wear on the inside of the barrel. The
bullet does the work, removing the copper fouling just speeds
up the process. Merry Christmas.