barrel break in pictoral log

[taliv]

it occurred to me that some of the discussion around this contentious topic could benefit from illustration. i.e. if we could see and have a common experience, we may get closer to understanding each other.

So as I just put my 11th 260AI barrel on last night, and took it out today to shoot it for the first time, I thought I would take a close up picture of each patch as I do my version of 'break in'.

my process is simple:
shoot a round, run a patch SOAKED in shooters' choice, wait 10 min, then run patches through til they come out mostly clean and dry.
repeat this until the 2nd patch shows no copper fouling

In this case, you can see a moderate amount of copper on the first round, a lot less on the 2nd round, and almost none by the 3rd round. So, the process involved a total of 3 rounds. On some barrels, this process has taken as many as 6 or 7 rounds. On some, I had no blue on the 2nd round. 3 is pretty average in my experience. So that's a pretty big contrast to the crazy 100+ round procedures some have described.

anyway, this is what it looks like when I do this:

ROUND 1

Note as I push the first patch through, it is soaked in copper solvent. So it picks up a lot of carbon, but the solvent hasn't had time to start dissolving the copper, so you don't see any blue yet.


10 minutes later, the solvent has done its work and the results are obvious. I say this is a moderate amount because I've seen some with a lot more and some with a lot less.



2 more patches and the solvent has been wiped out of the barrel, taking with it most of the carbon and copper.


ROUND 2

round 2 fired, and another solvent soaked patch pushed through the bore.


10 minutes later, the solvent has again done its work, but we see much, much less copper this time. We know the solvent works, so the inevitable conclusion is the second round simply left less copper in the barrel than the first round. The theory is that this is because the tooling marks from the finish reamer in the throat got smoothed out a bit by the first round, and thus scraped less copper off the jacket.



two patches later and the solvent is again wiped out of the bore and patches are pretty much clean. (I don't keep running patches until the carbon fouling stops because I'm eventually going to want my barrel to remain at a stable level of much more carbon fouled than this. I just want to make sure I get the wet solvent out so the barrel is dry.

 

[taliv]

ROUND 3

3rd round fired from this barrel, and another solvent soaked patch pushed through the bore.


10 minutes later, another patch goes through and shows almost zero copper fouling. Again, we know the solvent works, so if there was copper in the bore, it should show up as a bright blue patch. We are left to conclude bullet 3 left almost no copper in the bore. Looking at the close up picture I can see a tiny hint of blue sort of in the top center, so if I'd seen that when I was on the range, i might have done a 4th round, but probably not.


3rd patch... i wiped off the entire length of the cleaning rod with this patch, so it was a lot wetter than normal.


4th patch looks clean and dry.
Process complete. 3 rounds fired, 12 patches used.



So again the goal is to reach a stable point in fouling a barrel. Since our barrel isn't copper fouling anymore, we only have to deal with carbon fouling. But as a proof point, after 25 total rounds through the barrel (all I fired at the range today), I cleaned one more time. If any of the next 23 bullets had left copper in the bore, we will see it on the second patch....


ROUND 25

After 25 rounds, a solvent soaked patch is pushed through the bore.


10 minutes later, we push the next patch through and to no one's surprise, it shows not a hint of copper fouling.



2 more patches run through to make sure the solvent's out and barrel is dry.

In my experience, the next few hundred rounds or so will look substantially identical, with no copper fouling. Eventually the throat starts to get that cracked lakebed effect and the copper fouling begins again.

just a gratuitous internet group picture:
during those last 22 rounds, I got the zero close on elevation, left windage about .3mil left. I'll get a better zero after I work up my match load. I also shot three 5-round groups and a 3-round group, pictured below. The shoot-n-see dots are 5/8" for reference. the target is an IPSC silhouette I had shot el Presidente on yesterday a few times. group sizes were:
3-round - 3/8"
5-round - 1/2"
5-round - 3/8"
5-round - 5/8"
it was 30* and windy and i was freezing. my wobble was at least 1/4" so I'm pretty confident the rifle will shoot a lot tighter when I'm wearing more appropriate attire.

 

[Geno]

That's an interesting process. Thanks for sharing it.

Geno

 

[Howard Roark]

Nice write up taliv.

It would be interesting to compare how many rounds and patches it takes a lapped button rifled barrel to clean up vs. lapped cut rifling barrel vs. factory unlapped barrel.

One of the best shooting .223 barrels that I ever had was a Douglas CM that looked like a copper mine it's whole life no matter with what or how I cleaned it.

I see that you use H 4350. I've shot many jugs of IMR 4350 in my .260's. Have you tried IMR and if so what are your thoughts between the two?

 

[Reloadron]

Interesting and thanks for sharing that taliv. Pretty cool results.

Ron

 

[taliv]

thanks. that would be interesting. the first of my 260AI barrels was a broughton button and I did NOT do this break in on it, iirc. The other 10 have been bartlein cut. so i really couldn't say if there's a difference. I doubt there is though, because I think the copper comes from the throat, not the barrel, so the rifled part is cut away by the reamer in the chamber and is irrelevant. just a theory though.

To be clear, I am not claiming this makes a rifle more or less accurate. only that it is likely to affect how much copper you see in the barrel later in life. and i believe it affects SDs.

I only shoot H4350 because of its insensitivity to temp changes. Never tried IMR, but some friends have because it's cheap. Seems to work well for them. I have used more R17 than H4350, but am wanting to try the new IMR enduron or whatever powders because I've heard they burn cool and R17 burns super hot.

 

[CPLofMARINES]

Outstanding, thank you for the detailed writing and photos.

 

[Howard Roark]

I think the copper comes from the throat, not the barrel,

Yep.

I have a pound of Enduron 4471 that a friend gave me to try. He was not impressed and gets better groups with H4350 in his .260. My IMR was very cheep, I got 16# for free so I'll be burning it for a while.

 

[Speedo66]

I didn't see if you mentioned whether you cleaned the barrel before you shot it for the first time?

 

[desidog]

A new barrel and you already chipped the paint! Or did a drip of the copper remover do that? Why the bare threads?

 

[MtnCreek]

Thanks and great shooting. What type of grease are you using on the threads?
Thanks.

 

[taliv]

Definitely clean the barrel before the first shot but there's no fouling so no reason to use solvent. You're just making sure there's no metal shavings hiding in there from when the chamber was cut. (edit: assuming we're talking about a hand lapped custom blank. God only knows what you might find in some factory barrels)

I shoot with a suppressor that I thread on. Have to remove it to clean.
I'm rough on paint but I rushed my gunsmith and instead of putting cerakote on it he just threw some rattle can paint on there and overnighted it to me. Gotta get ready for a match coming up.

A generous friend who works in a nuclear plant gave me a can of nuclear grade anti seize. If you're wondering why it's a little fuzzy it's because I destroyed the inside of my suppressor cover and the insulation is having a bad hair day and getting caught in the threads. I need to get that fixed

 

[horsemen61]

Thanks for the write up

 

[MCMXI]

taliv, my two Krieger barrels took three and five rounds to "break in" (polish the throat) using a process very similar to yours. I recently received a 6.5 Creedmoor barrel (Bartlein) for one of my AIs and no doubt will follow a similar routine. Nice posts by the way.

 

[taliv]

thanks for the extra data points, 1911. I was sure i wasn't alone


btw, i want to clarify the point about the throat being discussed, as some readers may misunderstand. Many claim that hand lapped barrels do not require any sort of attention after they leave the factory. They make some statements that the barrel makers make them as smooth as they can be, etc. That's all fine by me.

The issue is that AFTER they are hand lapped, they go to a gunsmith, who cuts a chamber in them. A good bit of the metal in the bore that is so carefully hand lapped then winds up shredded into tiny chips, scattered in puddles of oil all over the lathe and floor. The fresh surface on what is now the throat was never touched by the barrel maker.

Also, the assumption is that the copper is not scraped off the jacket as it rides down the bore. Rather, it is scraped off in the rough throat, suspended in the gas, and then deposited as the gas cools in the bore. Another assumption is that copper adheres to copper and so if there is copper in there, copper will come off the jacket as it rides down the bore and may continue to build up. I can't prove either of these, but they are consistent with my observations. If the copper was initially scraped off the jacket by the bore, it's not clear what mechanism would cause the fouling to stop.

Another assumption is that if a one is a little sloppy or lets the reamer get dull like a factory might compared to a custom gunsmith that takes a little more pride in their work and charges a LOT more for, a rougher chamber or a burr could continue to cause fouling for dozens of rounds. this means you could have a much different experience than 1911 or I described.

Finally, I've never done this for chrome lined barrels, but like Howard Roark said, it would be interesting to do a comparison. My assumption would be if the chrome is added to both the barrel and chamber, it would be completely smooth with no seam. Next time I build an AR, especially with a cheap barrel that is chrome lined, I'll do this test and expect to see no blue on the second patch.

 

[MCMXI]

taliv, I'd like to add that I used to shoot 80+ round matches using those Krieger barrels and saw no POI shift due to fouling. After the initial copper removal they never fouled again. A barrel that shoots the same whether cold, hot, clean, dirty, round #1 or round #100 is a beautiful thing.

 

[taliv]

exactly! i see a slight (10-20 fps) change in velocity from a totally clean barrel to a stable carbon fouled barrel. but the POI doesn't change at short range.

 

[MtnCreek]

nuclear grade anti seize

Next time I'm in Lowes I'm going to ask for a can of this. Should be interesting.

 

[taliv]

heh, bring your go-pro!

 

[Frostbite]

Taliv, thank you for your posts. I now understand break in procedure and its usefulness a little better. Telling the truth, I always thought there was a little voodoo into this.

I have heard about and read about some 100 shots recipes also. Do you think they would do any better for a regular factory barrel? Are you of the opinion that a factory barrel would benefit at all from any kind of break in procedure?

 

[taliv]

honestly, i don't know. If I had a factory precision rifle barrel, like a savage or ruger precision rifle, i would do this break in on it, and if it was still copper fouling after 10 tries or so, i would give up and just shoot it. no way i have the patience or attention span to do a 100 round break in.

if you have the opportunity, please try it and post your results. i'd like to know as well

 

[ontarget]

I have a new rifle a Savage 111XP that I have put 12 rounds through. Is it too late to try this procedure? And do you think I could benefit from it?

 

[MCMXI]

taliv, I'll document the same procedure on the new Bartlein barrel for my AI when I screw the barrel on shortly.

ontarget, if you remove all copper to expose any toolmarks in the throat you'll be able to polish them out sooner. The procedure described by taliv expedites the polishing.

 

[taliv]

ontarget, no idea, but would be interesting to try. my guess is you will have more copper and might have to run 2 or 3 solvent soaked patches through before you fire the next round. but if you get to the point where the next round isn't fouling, you will have accomplished the same thing. post pics when you try it.

1911, cool. i'd like to figure out a similar way to document how much copper is in a barrel when you don't do this, but obviously this act of observing changes it. bore scopes are interesting but you can't really measure and you can't see anything with all the carbon in there anyway

I have heard about and read about some 100 shots recipes also. Do you think they would do any better for a regular factory barrel? Are you of the opinion that a factory barrel would benefit at all from any kind of break in procedure?

perhaps a more direct answer depends on what they claim to do. i like to take a scientific approach. try to design a test that addresses the claim. until someone says what a 100 round break in procedure supposedly accomplishes, i would have zero interest in it. the "break in" above definitely does something. it stops copper fouling. so it's demonstrably not voodoo. of course, we can debate whether copper fouling is good or bad. plenty of people believe you "need to lay down a bed of copper to fill in the pores in the steel". I don't subscribe to that view, but i guess we need to design another round of testing

 

[taliv]

to show continued absence of copper fouling, i decided to clean again, twice in a row, after 70 rounds today. pics below. as expected, no copper (blue) whatsoever. I cleaned twice in a row and you can also see how little carbon came out the second time. good barrels really clean up fast. i also used probably an excessive amount of solvent on the first and 5th patches. again, roughly 10 min elapsed time between 1st and 2nd patch and 5th and 6th patch to give the solvent time to work.