I started experimenting with the one-shot-clean (or 3-shots-clean, or whatever) break-in method around 25 years ago, partly because Ross Seyfried reported on it favorably in Guns & Ammo, and I generally believed what Ross wrote. (Knew him pretty well before he mostly gave up gun writing.)
I eventually quit breaking-in barrels that way because it resulted in very different results in various barrels, both factory and various quality custom barrels--and I generally found the same thing happened when I just cleaned the barrel after the first few 10-15 shot range sessions.
Why wouldn't the bullets "burnish" the throat and barrel the same way if it's cleaned down to bare steel after each session? (Eventually I also wondered why so many advocates of that break-in technique always seemed to use the word "burnish," which is a synonym for "polish" in every every dictionary I've ever checked. Have mentioned this before in various places.)
Not long after starting my experiments, I also bought a Gradient Lens bore-scope, due to realizing I needed to see exactly what was going on inside the bore--including seeing if WAS perfectly clean between shots. Still didn't find any consistent magic in the technique--and then, not long afterward, Ross published a column in Guns & Ammo that he'd changed his mind--that he'd decided the technique was essentially BS.
A few years afterward, around 2006, Dyna Bore Coat came along, and after experimenting with it considerably, decided it was a far better solution for bores that tended to foul, particularly factory barrels, but even lapped custom barrels. In fact I installed it in the Lilja stainless barrel on my last custom rifle, a 6.5 PRC by Charlie Sisk. The Lilja didn't foul much, but more than I suspected it would after installing DBC--and I was right. It doesn't shoot any better than pre-DBC, but it shoots great--and needs cleaning FAR less often.
John
JB,
Burnish is a technical term in machining that is a distinctly different process than polishing. Burnishing is a cold working process that does not remove material with an abrasive.
Based on my experiments and tests a build up of fouling slows the burnishing process down so cleaning somewhat more fequently at the begining of a barrels life can get the surface finish of the barrel optimized sooner.
A Tier 1 barrel in .223 Rem will probably get as good as it ever will with 20 shots and 3 cleans.
A Tier 1 barrel in 7MM Mag will take 5 cleans and 25 shots to optimzed surface finish.
As you have a bore scope it's pretty simple to see the anular tool marks in a throat smooth out and the deposits of copper dramtically reduce.
It not that shooting to many rounds early on will hurt a barrel and if a guy does not want to clean at the range nothing will be harmed by cleaning to bare steel when he gets home, it just slows down the burnishing process.
I think we are agreeing that a few number of cleanings to bare steel get a barrel to it's best finish and I find it faster to get to best bore finish by cleaning at the range and shooting fewer shots between the cleans.
We also agree that Dyna Bore Coat is good stuff.
JB
Originally Posted by 5sdad
John, the use of burnished instead of polished is just another example of a more pretentious word being thought to sound more intelligent than does a simpler word. See also: velocity for speed and ambient temperature instead of surrounding temperature or just plain temperature.
This is how you tell me you're not a machinist without sayin "I am not a machinist".
John Burns
I have all the sources. They can't stop the signal.
I would love to know the technical difference in meaning between burnish and polish.
A few years ago I looked up both words in the two most accepted English dictionaries, Webster's Unabridged (for "American" English), and the Oxford Dictionary (British English), and they both said the words meant basically the same thing. (By the way, I also did the same thing not too long ago with "accuracy" and "precision," which some shooters claim have different meanings. Same deal. Both Webster and Oxford list accuracy and precision as synonyms.)
John
In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface.
John, the use of burnished instead of polished is just another example of a more pretentious word being thought to sound more intelligent than does a simpler word. See also: velocity for speed and ambient temperature instead of surrounding temperature or just plain temperature.
Velocity/speed and ambient temp/temp have important technical distinctions and meanings. But in daily conversation, it doesn't make much difference.
[/quote] In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface. [/quote]
OK, thanks for that definition.
I have another question: How does shooting copper or copper-alloy bullets through a steel barrel amount to "smoothing a surface by rubbing it with something harder" ?
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface.
It's not just "something harder" but I think we are on the same wave length..
A bullet at 65,000 psi is cold working the surface of the barrel and smooshing the surface finish of the bore.
Keeping the bore surface some what clean allows the bullets to smoosh faster on the rough areas.
That's not to say any amount of breaking in on a schit tier barrel will ever make it great.
John Burns
I have all the sources. They can't stop the signal.
In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface.
OK, thanks for that definition.
I have another question: How does shooting copper or copper-alloy bullets through a steel barrel amount to "smoothing a surface by rubbing it with something harder" ?
In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface.
It's not just "something harder" but I think we are on the same wave length..
A bullet at 65,000 psi is cold working the surface of the barrel and smooshing the surface finish of the bore.
[/quote] In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface.
Originally Posted by Mule Deer
OK, thanks for that definition.
I have another question: How does shooting copper or copper-alloy bullets through a steel barrel amount to "smoothing a surface by rubbing it with something harder" ?
Ancillary question: what wears out the rifling with copper jacketed bullets passing through the bore repeatedly?
Originally Posted by RJY66
I was thinking the other day how much I used to hate Bill Clinton. He was freaking George Washington compared to what they are now.
All cut metal have a bur like rough edge - but even leather can straighten / bend those burrs
Most high end barrels are already lapped - BUT when the barrel is chambered the throat area is freshly cut and people DO (not a question) notice that a rifle shoots better after 50 to 100 rounds are shot out of it… so some smoothing of the burrs are occurring.
Now couple that with the fact that different types of copper can make a barrel act screwy fast (change bullets and you change the copper), and you will all of a sudden realize a secondary benefit to keeping things clean until you find the load you are going to use.
I like keeping a barrel clean until I find the bullet it likes so the fouling is the same stuff..
Third an probably the most relevant - find me a shooter that is good enough to tell when a barrel shoots .5 MOA larger on any given day .. The guys that Yack the loudest aren’t typically in that group.
It amazes me that some think you can remove rough, tight, spots or whatever in a steel barrel by running 50-10 rounds if copper thru a barrel.
If some think so, take a fairly smooth flat piece of mild steel and measure the thickness with a 4 place micrometer. Then take some 400 grit carbide wet paper,rub it back and forth 100 times and measure the thickness of the steel steel again. It is darn hard to remove even .0002 from it.
If God wanted you to walk and carry things on your back, He would not have invented stirrups and pack saddles
My instinct is that elaborate barrel break-in protocols are one of those knee-jerk activities that seem to make sense and are mechanically parroted simply because they were mechanically parroted by somebody else, who parroted what he'd heard from somebody else. Whether such precautions are necessary or sensible doesn't seem to factor into the analysis.
The break in is a pain, but I do it for every brand new rifle. I'm not talking about a lot of new rifles...but went through the break in process 3x last year. All seemed to clean up easier after the break in process.
What I do like about going through the process is that it gives me real opportunity to see if anything isn't right about the rifle. The 3rd rifle last year was tough extracting from the magazine, chambering and extracting the fired round but those things smoothed out by the end of the break in process. What didn't was that the Mark Pro trigger was worse than I thought a trigger could be...wouldn't adjust, wasn't crisp, a POS. Gave me time to install a Trigger Tech and finish the break in.
In engineering (itself a term which has a range of meanings) "burnishing' is smoothing a surface by rubbing it with something harder, using cold-working not abrasives as John Burns said. It smooths without removing material. Polishing is using an abrasive to remove material to achieve a smooth surface.
Originally Posted by Mule Deer
OK, thanks for that definition.
I have another question: How does shooting copper or copper-alloy bullets through a steel barrel amount to "smoothing a surface by rubbing it with something harder" ?
Ancillary question: what wears out the rifling with copper jacketed bullets passing through the bore repeatedly?
The break in is a pain, but I do it for every brand new rifle. I'm not talking about a lot of new rifles...but went through the break in process 3x last year. All seemed to clean up easier after the break in process. .
My point is "break-in" happens anyway during what might be called "normal" shooting, whether you shoot one shot and clean the bore, or 10-15 shots and clean the bore. So why go through the "pain"? Instead just shoot the rifle, and while finding out what it tends to prefer it's getting broken in anyway.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
Same guys "break in" their rifles as change their oil at 1500 miles and mail it to a lab. Could spend that time mowing your yard for the sixth time that week instead...
The break in is a pain, but I do it for every brand new rifle. I'm not talking about a lot of new rifles...but went through the break in process 3x last year. All seemed to clean up easier after the break in process. .
My point is "break-in" happens anyway during what might be called "normal" shooting, whether you shoot one shot and clean the bore, or 10-15 shots and clean the bore. So why go through the "pain"? Instead just shoot the rifle, and while finding out what it tends to prefer it's getting broken in anyway.
