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Custom Barrel Care at 17X By Jim See

 
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  #22  
Old 12-23-2009, 10:08 PM
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Re: Custom Barrel Care at 17X By Jim See

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Originally Posted by wrad View Post
Jim - Nice write-up on cleaning and break-in. I am about to receive my first custom gun, a .338 wildcat with a 36" Lilja barrel. I want to treat it as royalty. I am an engineer with some training in metallurgy, and there is one question that I have never seen answered about break-in. I know one very successful mile shooter who does no break-in, and says he cleans his barrel "almost never." I know others who will clean after each group, if possible. So I am really perplexed.

The question: What does break-in actually do to the metal of the barrel? When you say that you fire the first round, then clean out all the copper, what has actually changed in the barrel to make the next round behave better? And each subquent shot & cleaning? Any metallurgist will say that sliding one little copper slug down a hard & polished steel barrel will not change anything. Copper is just too soft to move any steel around. If you tell me that the breakin pushes copper molecules into tiny pores in the steel of the bore, and those embedded molecules never come out, I can buy that. That would smooth over microscopic pores. If you tell me that it's not the copper, but rather the heat of the gases that somehow changes the surface metallurgy of the bore, and that cleaning out the copper after each round just allows the gases from follow-on shots to make better contact with the steel, I can buy that too. But I just have a lot of trouble believing that miniscule contact with soft copper that peals off a bullet will change the steel in any way. I really hope you or someone else interested in this aspect can explain it to me.

My Navy SEAL son-in-law said then never clean barrels. They don't carry cleaning stuff, and they don't want to change the way a gun shoots.

Thanks,
Walt
Lebanon, OH
Walt,

Here's part of an article found on Dan Lija's web site that lines up with what Jim said about carbon and barrel break-in...

Quote:
It is important to break-in a barrel though. The jacket material must be removed after every shot during the initial few rounds. If this isn't done the areas of the barrel that fouled will tend to pick up more fouling and it will build on itself. It is important to get a layer of powder fouling on top of the lands & grooves. This hard deposit will prevent the copper from stripping off the bullets. However, if the internal finish of the barrel is too rough the barrel will never be completely broken-in and fouling will always be a problem. Some barrels can't be broken-in.
A similar phenomonon can exist if the shooter uses an abrasive-type cleaner too often. The abrasives are very effective at removing all traces of both powder and jacket fouling. I mentioned that a barrel can be too smooth. The abrasives can get a barrel too clean as well and in effect the shooter is rebreaking-in the barrel again every time he cleans. This can end up in the dog-chasing-his-tail scenario. The shooter thinks the barrel is a fouler, as evidenced by the copper accumulations in the barrel. He works hard at removing the copper, resorting to using an abrasive cleaner. But when he does he removes the desirable layer of carbon fouling left by the powder and exposes fresh steel ready to grab some more copper off the bullet on the next shot. The cycle repeats itself. Like the dog the best way out is to go lay down and take a nap.

Lilja Precision Rifle Barrels - Articles: Barrel Fouling
I can't explain in detail what goes in the bore during the break-in process, but I have seen first hand the evidence of greatly reduced fouling. Maybe I can draw an analogy. Not sure if it's an accurate analogy but it makes sense to me. If you take a sharp knife and skin out a deer with it, it will get dull. The hide and flesh are nowhere near the hardness of the steel but they do dull the sharp edge of the steel. Maybe this is what is going on? Maybe the sharp edges of the steel and especially the edges of the rifling are being "dulled" by the velocity and pressure of bullet. As Lilja points out, some bores are too rough to ever be completely broke in and I have a coupl of those. They did show a reduction in fouling, but still foul a good bit. They are easier to clean though than the first time I cleaned them.

On regular cleanig... it's true that cleaning will usually affect a rifles POI right after the cleaning for maybe a few shots until it settles in again. But I can assure you, that with my rifles, when they get fouled to a certain point, which is usually around 50-70 rounds, the groups start opening up a whole lot. After a good cleaning and a few fouler shots, they settle back into their .5 MOA accuracy.

Mark

Last edited by MontanaRifleman; 12-23-2009 at 11:46 PM.
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  #23  
Old 12-23-2009, 10:36 PM
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Re: Custom Barrel Care at 17X By Jim See

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Originally Posted by mdw717 View Post
Thanks for writing this article Jim. Real world experience is always appreciated over theoretical conjecture. Can you explain what you mean here?

"One trick for determining the bores cleanliness is the q-tip down the muzzle. This will allow you to see if you have the copper out of the bore."

I'm following your advice breaking in my new 243 X-bolt.
Thanks. MW
Has any one out there tried using Molybdenum Disulfide coating the bore or on bullets? It lowered my zero substantially for the first couple rounds but then settled down. It will fill in some of the molecular flaws and helps reduce copper fouling but it will change your zero. It also makes your weapon easier to clean. The down side is that when you clean the bore it is difficult to see what is powder residue verses the Moly coating. A good bit of it will be on your patches for a while. Just thought I'd ask.
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  #24  
Old 12-24-2009, 08:48 AM
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Re: Custom Barrel Care at 17X By Jim See

John, I never really got on the moly bandwagon, so I can not comment on the stuff.

MW, The fellow with out a bore scope can take a q-tip and insert it about a half inch into the muzzle, then shine a flashlight into the muzzle. The q-tip will reflect back the light and you will be able to see any copper that may still be in that portion of the barrel after or during cleaning. This is a good test because in many barrels copper fouling seems to hang in there the most near the muzzle.
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  #25  
Old 12-24-2009, 09:21 AM
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Re: Custom Barrel Care at 17X By Jim See

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Originally Posted by Coyboy View Post
John, I never really got on the moly bandwagon, so I can not comment on the stuff.

MW, The fellow with out a bore scope can take a q-tip and insert it about a half inch into the muzzle, then shine a flashlight into the muzzle. The q-tip will reflect back the light and you will be able to see any copper that may still be in that portion of the barrel after or during cleaning. This is a good test because in many barrels copper fouling seems to hang in there the most near the muzzle.
Absolutely right on. I have found that using a brass brush and about 6 draws through the bore is all that is needed to get the copper fouling out followed by a nylon brush with a lighter cleaning solution. The Moly coating paid off for me. Muzzle Velocity for this weapon using exactly 71.2 grains of R-22 and seating the 210 Sierra BTHP Matchkings at .001 comes to 3056-3060 FPS at 600 feet above sea level at 70 degrees. The patch comes out clean. I also double the patches together for the tighter fit through the bore to really get into the groves. This barrel is a "Dan Lilja" (Plains Mont.) heavy barrel "tapered" 30 inch, 6 grove buttoned rifling, gas checked true 308 caliber set on the Rem. 700 large bolt, tweeked with a Sako extractor using the Jewell trigger and is chambered for 300 Win Mag. Akley improved(12-15% more combustion inside the case). The cleaning and accuracy were demonstrated with a three shot .523 inch group at 400 yards on the cross hairs of the target on Sept 9 2009(8 witness signatures) at the Elbert County gun club. These three shots came together after my fifth shot as I was still trying to get the proper powder load. This 3 shot group is a combination. I put two of the three in the hole and Donny Sanders put the other one inside the same hole. We had about a 7-9 MPH 3/4 value wind at the time of the placement. What I am saying is that with a few "sighters" fired before the three shot group the bore is at the point that will give the best results. I have not found any reloading books that give a starting or ending powder load for a 210 grain round...so I "guestimated". When the bore is absolutely clean(first shot) the zero is slightly below the mark. After a little powder build up it improves the accuracy of the weapon. Thanks for your input.
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  #26  
Old 01-03-2010, 02:30 AM
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Re: Custom Barrel Care at 17X By Jim See

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#3. Thats an easy one, yes. The possibility that that barrel will never come around is there, But you also have the perfect barrel to experiment with. So ask for some tubbs bullets from the trade or freebie forum and conduct your own experiment.
Coyboy:

Thanks for your advice regarding my factory rifle barrel. I have been considering having it re-barreled, but have decided to go ahead and experiment with it. I have a Tubbs fire lapping kit on order for this rifle. Just for fun, I have another one on order for a mauser that I put together with an A&B barrel. I will take careful notes and report back with my results.
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  #27  
Old 01-03-2010, 02:03 PM
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Re: Custom Barrel Care at 17X By Jim See

Enjoyed the article and yet there seems to be so many theories on break in. My sendero 7 mag is currently being re-barreled with a Hart, same caliber, but a 1in9 twist, 26" barrel. There website says there is no break-in since the barrel is hand lapped. I really want to be carefull with this barrel, so any suggestions from those who shoot Hart barrels. It won't be ready until the end of January.

Thanks!
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  #28  
Old 01-06-2010, 09:36 PM
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Re: Custom Barrel Care at 17X By Jim See

I'm curious what the purpose of the Kano is? If you plan on firing the next shot right away, is having a light coating of rust preventative in the barrel helping anything?
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