Home Forums Hunting & Shooting Hunting Rifles Barrel break in...myth or what?

I just bought a brand new, high quality rifle. What is the best way to “break in” the barrel? Thank you for any experienced feedback.

According to George @ Gap fire 1 round clean, fire 1 round clean. Shoot 3 shot group clean. Your barrel is now seasoned. Clean every 500 rounds.

Probably should ask your rifle manufacturer first. Some believe barrel break in works while others think it's a waste of time and money.
I followed the suggested break in for my last weatherby vanguard and it shot great. I didn't do any break in for my ruger Hawkeye or win m70 and the both shoot great, so who really knows? Good luck with your rifle.

I tried the break in theory on one gun and just spent a lot of time doing it. If it shot better afterwards, I couldn’t tell. I have owned dozens of new rifles that I just cleaned the bore, mounted the scope and went to shooting them. I seem to hit except when I miss and I doubt it has a thing to do with barrel break in...

If anyone knows, this just might be the guy to pay attention to!

You can find the video on YouTube. His theory makes sense. Notice he doesn't go crazy.

Waste of ammo.

But hey, much of confidence takes place between the ears. Magic feather worked for Dumbo.




P

I'm on a search

I clean them throughly when i first get them, then fire about about 20 rounds or so getting the optic set. I clean them again down to the steel (verified by bore scope) and start load development. Once i get my load I clean them down to the metal again and live happily ever after and let the barrel tell me how often it needs to be cleaned.

Sam Millard of Pan Handle Precision, is another minimalist in his ideas about break-in and cleaning. I’ve done it a bunch of ways. There are just too many variables, but often times the most important cleaning is the first one. So, while the amount and exact content of the crud lining chambers and bores of new rifles is varied, it’s almost always there. Particularly in the case of factory and semi custom rifles.

Who made the rifle?

No waste of ammo. First two rounds are sighting in, next three are your three round group. You're done. Where is the waste? That is why George building sought after rifles, and you sell Pharm.

Instead of putting my facts on the sight so other's can write it off as opinion let me ask you this!

What is the hardness of your average steel centerfire rifle barrel?

What is the average hardness of copper alloys used to jacket lead bullets?

Do you have to break in the chamber by expanding 70/30 brass cases into it? Oh and so you know the 70% is copper the 30% is zinc.

What causes most barrels to be shot out? Is it rifling wear to the lands or groves? Is it throat and crown erosion?

What causes throats to erode and crowns to erode?

If you look at the tools used to make a barrel and then look at what a bullet is made from it is a fools folly to think you can break in a barrel by passing a copper alloy lead slug down the bore. The abrasion comes from powder and heat and pressure of the combustion is what does a barrel in not frictional mechanical wear. That is also why you can look at a Savage barrel for instance after 1000 rounds have gone down it and if you ignore the throat and crown it is still looks nasty and rough nothing has been worn down. If you look at Remingtons pre-CHF you will see all kinds of artifacts that have been their since the barrel was made even 5000 rounds later. Last but not least if break in was a real thing and not magic nonsense then taking a 1/4 inch off both ends and rechambering and recrowning would not work as consistently as it does to restore 90% of the original barrels accuracy as often as it does (not talking about BR levels of accuracy for the record)! The US Army requires or required 20K rounds of accurate fire on the

I'm not a bench rest shooter.
I'm also not near as anal as I once was when it comes to accuracy.

My barrel break in proceedure.

I add squirt or two of Kroil to a jar of JB Bore Paste. I use a bore guide. I liberally cover/saturate a bronze bore brush with the JB/Kroil paste. I put 50 strokes or 25 cycles minimum, though the barrel. If I decide to do more, I change out the bore brush and do an another 50.

Then I clean to bare metal.

I go and shoot. It usually takes 8 to 10 rounds to foul the barrel in. I'll usually shoot at least 20 rounds or so.

Most times that is my barrel break in and I do not clean for another 75 rounds or so. I'm not shooting moly or black powder and my rifles are stored in an atmospherically controlled low humidity environment.

If I'm feeling energetic, I might do the JB/Kroil bore brush thing once more after the first range session. These days I'm not doing much load development as over the last 25 year or so, I've developed pet loads.

I always foul in the barrel after cleaning, before hunting the rifle.

Anywho,. Does this routine break in the barrel. Don't know, don't really care. I've owned and shot a lot of rifles and it works for me.

Merkel K3 Extrem, 270 Winchester



Doing the JB Bore Paste/Kroil thingy!




Shots 1 & 2 @ 25 yds to get on paper. Factory 150 grainers.




shots 3-5 @ 100 yds., for zero. Factory 150 grainers




Shots 6-8 @ 100 for zero. Getting serious. Using my "go to load" for the 270 Win., 130 gr. Accubond handloads




Shots 9-11, @ 100, and where I called it good. 130 gr. Accubond handloads



After this, its first shot out of a cold barrel to check for zero.


YMMV


ya!


GW

Starts detailing cleaning procedure and theory at 4:30.

Krieger knows what they're talking about. I followed their recommendations for the three that I owned and use the same process for new barrels that are of good quality. With a good barrel it's all about polishing tooling marks in the throat. You can do it in three to five rounds in the first range session or three to five range sessions cleaning each time when you get home.

https://kriegerbarrels.com/faq#breakin

Easy there, Homer. I’m not referencing George’s protocol, it doesn’t sound much like break in.

And I like selling drugs. I make enough money to buy George’s rifles.




P

It wasn't a jab at you. Just rebutting your remarks of a waste of ammo. Nothing wrong with selling drugs or medical devices I have a bunch of friends that do it.

We've got a gunsmith near me that's done work for a couple of buddies and myself. His name is Don Geraci and in the 1980's he held a bunch of benchrest world records, he's in the benchrest hall of fame, etc.

He tells me to do a break in procedure like Krieger recommends so I do it. I figure if Krieger & a guy with a bunch of shooting records says do it then I'd probably better listen to them.

I only do it with good custom barrels. I don't worry about it with factory rifles, you're not going to smooth out a $20 barrel.

I've never quite figured out why a guy would buy a maker's best grade of barrel, handlapped and checked for straightness, have it installed by a good gunsmith who I would think would check for burrs and smooth out his work and sharp edges, and use well prepped loads in said well prepared, polished, and lapped barrel- and think it needs to be further broken in?

I can see it in a factory assembly line barrel where they are cut, drilled, and the rifling gouged out with a hydraulicly pulled rod , leaving lots of microscopic burrs and voids. A bit of polishing might be due in that case, along with filling some of those microscopic machining voids with gilding metal in order to create the illusion of a smooth surface, but isn't the point of having a premium barrel to avoid some of the inconsistencies and mass produced issues of factory arms?

Just my 2 cent's worth- I'll get my nomex underwear on now and pick up some popcorn while I'm at it.....

Bob

Sounds about right Bob. By the way, how's the weather out your way?

As George Gardner says it's not break in, more like seasoning. Watch the video it make make sense to you.

I used to follow a break-in procedure like Krieger barrels recommends. Once I moved to AK and lost access to private ranges where I had the time to clean between shots I quit doing it. I can't tell if I get any more fouling than I did following a break-in procedure, but I'm not shooting competitive either.

“Break in” procedures are self abasement.


Load, shoot, repeat.

In my experience there isn't a one method fits all. There are way to many variables to consider.....Design/method of rifling, quality of cutter, button or mandrel, quality of steel etc. etc.

There are several different techniques used for rifling a barrel - cut, button & hammer forged being the most common, and numerous rifling designs such as 5R, polygonal, 3 groove, 4 groove, 6 groove etc. A "break in" technique or method often suggested by a manufacturer for one type of rifling (Krieger cut for example) may be different for another manufacturer or type of rifling (Lilja button for example).

In my experience cut rifled barrels (even those hand lapped and produced from top quality barrel manufacturers like Krieger & Bartlein) require quite a bit more "break in" and shots before fouling is in check and top accuracy is achieved.

Button rifling and hammer forged rifling generally don't require the amount of break in or shots fired before fouling is in check and top accuracy is achieved. This too depends on a lot of variables including condition of the button or mandrel.

Using a good borescope goes a long way in determining bore condition and when break in or cleaning is needed..

I run a patch with Hoppe’s No. 9 through the barrel of a new gun and head to the range. Do my best to allow the barrel to cool down a bit between shots (also try not to heat up the barrel on my ‘older’ guns).

Only barrel I ever broke in was the $249 Vanguard I bought last year. Did it to avoid warranty issues in case of accuracy problems, and maybe just to gave the experience. Boring!

My two favorite writers disagree on this. JB seems to think it's unnecessary; Brian Pearce seems to do it quite a bit, and from his articles, I'd say that it at least may speed up the break-in that ordinarily occurs with normal use.

Take your pick. As a lazy old fat man, I'm siding with Mule Deer, unless the maker if an expensive rifle insists on it as part of their warranty. Thankfully, Barrett doesn't.

I pretty much do it as George Gardner describes in the video above.
Side note and somewhat unrelated - I've never met George but after watching enough videos featuring him, I'm pretty sure I could be fast friends with him - very pragmatic and unassuming.

Barrel break in - does 2 things accuracywise - and the 3rd impacts cleaning

1) is smoothes the machining marks if the barrel wasn’t lapped.

2) it leaves some copper which normalizes how bullets shoot (note changing bullets that have different types of copper jackets will push the barrel into shooting wierd until the new copper is more coated...

3) Cleaning - smoothing the bore by shooting it.... of course makes it easier to clean.

- Considering all 3 - cleaning while shooting the first so many shots (breakin) gives you a more consistent smoothing & copper coating (no powder junk) so it’s beneficial to cleaning, and performance..... But if it’s lapped... you won’t need it as much.


SO - Breaking depends on what your shooting - at the end of the day if you are an accuracy nut - barrels “settle” down fairly fast, but really start performaing after 150 rounds.
for your typically field shooter the first 5-10, at worst 25 shots do it....

Wipe the bore clean first...then go shoot it.


Till you're done.


Then you can clean the bore again if its something you feel strongly about.

Like it. I feel break-in is a waste of time and effort.

It all depends on if you goal is minute of a dime , or minute of a pig , accuracy.

Today's manufacturing procedures, along with more consistent steel manufacturing processes, and add to this, much cleaner burning powders, had made barrel breakin's more of a thing of the past, but that doesn't mean its not a good idea, especially for those big bores, burning lots of slow powder.

This like the Chevy / Ford arguments, men will do what ever they were told first and foremost !

1. Clean bore
2. Get on paper
3. Shoot groups

Exactly. How could you tell, what would you be comparing it to?

Just curious, not referring to a full on cleaning but do you guys pull a bird snake through from time to time?

I've done this, but I won't wait 500 rds before I clean it again, ha. I try to clean every 20-30 rds or so.

I've never seen the difference..

[/quote]


Totally agree. Just go shoot the damn thing! If the groups start opening up, then clean them. All my rifles have been great-shooters and I have never done a "procedure", for break in.

This is close to what I do minus the bore scope , don't own one.

No...set it aside during a busy shoot, let it cool while you are shooting rifle #2

All barrels shoot better after a few rounds have been through them. Some may only need a dozen or so before reaching optimum accuracy potential. Others may need 200+. But as far as a strict routine of firing X number of rounds, cleaning,and then firing 2X number of rounds and cleaning again I ain't buying it. The barrel can't count. Shoot it, clean it when it is dirty. It'll get better over time and get easier to clean.

I’m not arguing for one way or another. I’d just point out that those being adamant that a softer metal can’t polish/wear a harder metal, have maybe never stropped a knife blade on cloth or paper. Heat does stuff. Just saying.

or 3, and 4, and 5, and 6

ya!


GWB

Watched a video once, some of it depends on if it’s a bull barrel or cow barrel.....

Now you've done it!



Proper break in proceedure of a bull-barrel. Cow-barrels need not apply!

TFF.

ya!


GWB

Bob[/quote]
Sounds about right Bob. By the way, how's the weather out your way?[/quote]

Weather report of the "storm of the century" was premature at best. A few flurries and melted right off. Dry right now but now the report says rain for the next few days.... hope there is a little tracking snow next week for the 11th Lion hunt in Lapine...

Bob

I will ask one more question: What will a softer metal (copper jacket, lead core) do to steel once it is accelerated to 3000 FPS?

One of the best videos Stick ever did. Kind of a public service announcement ala Big Stick style...

Bob

10/4

Cow Barrels, WAMs and Texans!

Like I mentioned before,

TFF.

ya!

GWB

quote] ..... Lija barrels FAQ

Q. Does Lilja have a recommended cleaning and break-in procedure?

A . Yes we do and it depends on the type of barrel: rimfire, centerfire, .50 BMG

Break-in Procedure (centrefire)

For an effective break-in the barrel should be cleaned after every shot for the first 10-12 rounds or until copper fouling stops. Our procedure is to push
a cotton patch that is wet with solvent through the barrel. This will remove much of the powder fouling and wet the inside of the barrel with solvent.
Next, wet a bronze brush (not a nylon brush) with solvent and stroke the barrel 5-10 times. Follow this by another wet patch and then one dry patch.
Now soak the barrel with a strong copper removing solvent until all of the blue mess is removed from the barrel. The copper fouling will be heavy for
a few rounds and then taper off quickly in just one or two shots. Once it has stopped or diminished significantly it is time to start shooting 5 shot groups
, cleaning after each one. After 25-30 rounds clean at a normal interval of 10-25 rounds. Your barrel is now broken-in.



Q. What is hand lapping?


A. The hand lapping process, that all of our barrels undergo, ensures that you will receive a rifle barrel that has the very best and most desirable type
of internal finish that we can provide. The lapping operation brings the final internal dimensions up to size and also improves the finish. No production
barrels are hand lapped, only the finest custom barrels receive this very important operation. And it is partly for this reason that hand lapped barrels
cost more than lower grade production barrels.

In practice, a lap is cast around a rod placed inside the barrel. The profile of the rifling is cast into the lap ensuring a very precise fit with that individual barrel.
The lap is then “charged” with lapping compound, oiled, and pushed and pulled repeatedly through the length of the barrel. The lap is “recharged” and oiled
many times and several new laps will be cast before the lapping procedure is completed. The man doing the lapping judges when the barrel is finished by a
very experienced feel for the job, inspecting the internal finish as it develops with a full length borescope, and by measuring the diameters of the lands and grooves.

We have, over the years, developed a process that we feel gives us the very best finish and uniformity of diameters the full length of the barrel, that we can obtain.
And the proof is, in our opinion, in the very minimal amount of bullet jacket fouling that our barrels produce, and in their outstanding accuracy.

Our process completely eliminates tooling marks from the inside of the barrel. And very importantly the resulting finish runs parallel with the rifling.

*********

Over the years we have developed a proprietary lapping system that allows us to create a superior internal finish. We have found through our testing what
is the optimum lapping material and grit. With the finish our barrels are shipped with (especially the stainless steel barrels), bullet jacket fouling is almost
nonexistent, and accuracy is at its peak.

One of the reasons we believe that fouling is minimal has to do with the direction of the surface finish in relation to the rifling. When a barrel is lapped,
the resulting surface lies parallel to the rifling. The bullet does not have to rotate “against the grain” as it would have to with an unlapped barrel or with
a barrel treated in another manner.

Another factor in surface finish has to do with its smoothness. While it is very desirable to have a finish running parallel to the rifling, the finish can be too smooth.
In our extensive testing we found that a lapped barrel could be made too smooth and that these super smooth barrels would foul more than our conventionally
lapped barrels. We have drawn an analogy between these “too smooth” barrels to racing slicks on race cars. These tires have no tread so they can get better
traction (or more friction) on the asphalt or concrete surface. It seems as though a similar situation results between a bullet and barrel if the finish is too smooth.
But in this case, the result is increased fouling, not increased performance.

Break-in would also somewhat smooth out the surface following lapping.

abrasives still leave micro peaks and troughs.

and different folks use different grit sizes of aluminium oxide or silicon carbide abrasive.

Tag
YouTube video barrel life at 20 minutes

I lap with boolits.

Hint.............

If you are using a custom barrel that has already been lapped by the maker, the only tooling marks left are in the throat from the chambering reamer/throating reamer. Those will be smoothed out by any of the already mentioned procedures. If you want to smooth out the throat before shooting, a little JB (the light brown, not the red) on your choice of mop or patch applied in and out a number of times through the throat only, followed by a cleaning of the full barrel will do.

Pass the bullets and hold the Fluff.

Hint.............

Classic film....

Legendary +P+.

Hint..............

I've probably read about 100 threads about barrel break in and there is one thing that I have NEVER heard defined. That is what constitutes a barrel that is broken in. In this thread we have had posters share their methodology but no one ever says that if X happens then the barrel is officially broken in. Shoot one, clean, shoot another one, clean, shoot three, clean doesn't tell me chit about what's going on inside the barrel. I've broken in a bunch over the last 45 years and my definition is that when a barrel quits copper fouling heavily on every shot it is "broken in". My exposure is mostly with BR quality barrels from most of the top shops in barrel making and I've had barrels that broke in with one shot and never fouled much again and I seen some that continued to foul for nearly 100 shots. I gave up on the 100 shot wonder barrel and vowed to burn that SOB to the ground in a P-dog town. It broke in and stopped fouling some where north of 100 shots. I've had only one premium quality barrel that never broke in and continued to foul and never quit. It was a Hart that in my view was too smooth. Many other barrels broke in in a more typical 5 to 10 shots. If I apply my definition across the board I contend that the majority of factory barrels NEVER break in because they continue to foul their entire lives. It is therefore a total waste of time, effort and money to even attempt to break them in. Load em up and shoot em is about as good as it gets.

.

Absolutely classic.

I did the shoot 1, clean voodoo routine ONCE! A very long time ago.

Never again.

Lija also claims barrels can be too smooth ,contributing to increased fouling...but I cannot get my head around that theory.

The smoother something is, typically the less friction you will encounter when it comes to metals - and if removing machining marks
reduces fouling, then would not also reducing a more aggressive lapped surface to create a smoother surface with better [lower]
co-efficient of friction be even better for reducing fouling?

Finer /less aggressive surface finish would create smaller micro troughs where contaminants can lay up.

Some might claim a smoother surface increases contact area between bullet and barrel, but that may not necessarily
be the case, you might just end up with a larger number of shallower micro peaks/troughs rather than a lower number
of more aggressive micro peaks/troughs. without changing the actual contact area by much.

same goes with barrels with differing number of lands-grooves,..ie; more or less may not alter actual contact area
between bullet and barrel...because one can compensate by altering the widths so that contact area remains consistent.

Vudoo break-in,is CRITICAL too.(grin)



Hint...............

Myth

Break in is a waste of time.

smy1, I'm glad a fellow Okie posted this. On a lapped custom barrel the throat from chambering will have a little machining fluff. My break in procedure is a small amount of xxxx steel wool wrapped around a bronze cleaning brush and with a hand drill lap the throat for a few seconds. Run a wet and dry patch through it and you are done. I haven't had a factory barrel in years, so can't speak of them.
I don't know any custom maker that laps any finer than 320 as a polished bore will copper foul moreso with a slick bore.
Now in a month or two another thread will spring up again on this subject.

I'm about to find out if a more aggressive lapped finish will solve that barrels fouling issues. I lapped it with 180 aluminum oxide at the advise of a gentleman who lapps barrels nearly every day. I'm going to shoot it and see if it breaks in or not. Should be interesting.

180 is akin to sand blasting a bore.

Hint...............

I kinda like Brux Barrels recommended break in procedure. "Just shoot the damn thing" lol

Ooooopsie!..............

I'll acknowledge your expertise with regards to sand in a barrel.

BARTLEIN barrels say that increased roughness causes increased fouling.

The various fire lapping kits on the market can include abrasives down to 400, 600, 800 and 1200 grit size.

Regarding the claim that a 'too smooth' bore increases fouling- maybe those who push that theory can provide
and explain the suppprting science/physics behind it.

I picked up a Rem 700 in .308 SPS stainless that I installed a new Shilen Match select barrel. I followed a buddy of mines break in and I thought he was completely nuts. But I wanted to shoot so I went to the local "Wally World" and picked up some $12 a box Remington core locks. Per his procedure:

- Do 5 shots, clean after each shot
- Do 5 - 2 shot groups, clean after each 2 shot group
- Do 5 - 3 shot groups, clean after each 3 shot group
- Do 5 - 4 shot groups, clean after each 4 shot group

Used Wipe out bore cleaning solvent when cleaning. I can tell you that when I first starting shooting, I was getting somewhat pissed being this is suppose to be a great barrel an all. First set of groups were horrible which was understandable being any machining marks that were there, were being broken in. The more I shot, the better the groups, even with this cheap ammo. We decided to shoot some hand loads that drive tacks in his 5R mil spec .308.

Rem 700 .308 Shilen Select match 20" 1:10 twist.

155 Palma, 43.8 gr Benchmark, Rem brass, CCI, 2770 fps, 2.825"
125 Nosler BT, 47 gr H322, Rem brass, CCI, 3180 fps, 2.825"
165 Hornady SST, Rem Brass, CCI, but forgot to write down the other info.

With just a shot in the dark on a "recipe", we started. Below are the pics over layed at 250 yards. No pressure signs or any other issues. Needless to say, i was pretty impressed. In fact, my rifle shot his loads better than his 5R that he worked the loads up for. So considering at $12 a box and 50 rounds fired...... that was a well spent $36 for my barrel break in that I thought he was crazy for even mentioning it. But that is just my experience.

The last new barrel I broken in I did the following. Cleaned barrel and applied Dyna Bore Coat. Used five rounds to get the gun sighted in. And 9 more for load development. I then loaded 500 rounds of the best load. The next weekend I went out and shot all 500 rounds at prairie dogs over two days without cleaning once. When I got home I cleaned it with Wipeput and it wasng too bad. Loaded up 500 more rounds and repeated. After 1500 rounds it shoots just about like it did when I started, which is to say pretty damn good.
Probably broke every rule of break in and the instructions for DBC, but I am not losing sleep over it. I have better crap to do than fart around cleaning insistently.

Haven't shot a Virgin spout,in almost (2) whole days and can only speak in the first hand to 100's.

Hint...............

Feller, think about it! Ever pushed a clean finger across a clean piece of glass?

Pushing ones finger across smooth glass is easier to to do than across etched glass.
etched glass is rougher, more abrasive and thus more grippy. (has a higher coefficient of friction.)

Better you Explain what you are trying to say through science/physics and we will see if it stands up
to scientific scrutiny.

Apples and oranges. There's no disputing that a rough barrel will peel copper off a jacket like when you crashed your bicycle on gravel. The point that Butch is making is that a very smooth surface (think a polyurethane finish on a basketball court ripping your skin off) can accomplish the same thing. I hand lapped that Hart barrel and intend to shoot it soon and see if the fouling has been resolved. I'll post the results.

I've done break-ins and I've just started shooting them. Coincidence, maybe........but the most accurate shooters I have aren't the ones that got a break-in.

Waste of MY time. YMMV

My process is somewhat similar.

Fire three shots, don’t clean.





Fire three more, don’t clean.




Come back a few days later, fire three more shots, don’t clean.





Come back a few days later, fire three more shots, don’t clean.





Now, I had other rifles I was breaking in, so I didn’t go to the range just to shoot one rifle three times. Plus, it’s a Tikka, so that’s kind of like cheating.





P

Unprotected riders will leave more skin and flesh behind on a rough road surface than a basketballer will leave imbedded
in a polyurethane coated basketball court. To say those two surfaces are accomplishing the same thing/ result is nonsense...

Maybe You or Butch can explain how smooth glass or a smooth polyurethane finish creates/contributes to more fouling...???

AGAIN, , better to show the science-physics that supports the claimed theory that smoother surfaces create more fouling,
..but nobody seems able to provide such.

How about you assume the burden of proof that the statement is incorrect. Get yourself a top quality barrel from Lilja and polish it to a mirror finish (which should yield the ultimate non fouling barrel if your theory is right ) and see if it copper fouls or not. If it fouls call Dan Lilja and complain that it fouls and tell him you polished the [bleep] out of the barrel and ask for a replacement. You might be offered his insight on why he states that a barrel can be too smooth.

So when your 'smooth polyurethane basketball court' analogy and Butches 'smooth glass' analogy don't stand up
and you fail to provide any supporting Newtonian science,,,

you quickly pass the buck to Dan Lija to explain it.... ..LOL.

Dan Lija is on record for saying barrels can be 'too smooth' , however he does not technically/scientifically elaborate
or define what surface finish he regards as too smooth.
Whatever grit size Dan uses to lap barrels, , its obvious that its not considered sufficient to reduce fouling to his acceptable levels.
...He is very specific in explaining his recommended break-in process in order to reduce fouling in his new barrels.

Did you order the barrel yet? There's no science to prove it, and equally you have nothing to disprove it. Could it be that there are some shooters out there that have had premium quality barrels by the truck load over decades that come to a conclusion from experience? The same guys that have had some problem barrels that copper foul that were ultra smooth that formed their opinion. Could it be that a guy that's been in the barrel making business for nearly 40 years has some experience with barrels that have fouled and has formulated his opinion based upon experience? Nah, no way that could have ever happened in either case. Again, if your theory that the smoother the barrel finish. the less likely the barrel is to foul then how do you explain why no barrel maker tries to gain an advantage on his business competition by lapping to a 2000 grit finish. If it was a superior product competitive shooters would flock to them in droves. There's a reason they don't lap to those micro finishes. Butch says Shilen laps with 320 grit. I know there's barrels that are lapped with 180 aluminum oxide that yields a smooth enough surface to perform well without fouling. Wonder why that is?

Coefficient of friction. Two smooth surfaces have much more bearing surface causing friction. It's the same thing that allows a boat to travel much fast on slightly choppy water. When we are talking about a "rough" bore here, we aren't taking about rough in the sense of sandpaper stripping the copper jacket from the bullet. Only "rough" enough to reduce the friction.....

From Lilja's info referenced on page 2 of this thread.

Another factor in surface finish has to do with its smoothness. While it is very desirable to have a finish running parallel to the rifling, the finish can be too smooth.
In our extensive testing we found that a lapped barrel could be made too smooth and that these super smooth barrels would foul more than our conventionally
lapped barrels. We have drawn an analogy between these “too smooth” barrels to racing slicks on race cars. These tires have no tread so they can get better
traction (or more friction) on the asphalt or concrete surface. It seems as though a similar situation results between a bullet and barrel if the finish is too smooth.
But in this case, the result is increased fouling, not increased performance.

Stargazer, why do the barrel makers not use 400-1000 grit lapping compound?