Barrel breakin

[Jeff In TX]

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Factory barrels are a waste to spend any of that time.


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Roll-Yur-Own,

Not always so and with a as little as $75.00 some can be made tack drivers. I bought a Left-handed Winchester Model 70 Featherweight in 300 WSM. BTW my new nick name for this rifle is the "Mule". Can anyone guess why?

Anyhow, it would put the first two rounds in about an inch at 100 yards and throw the third shot left by 2 or 3 inches. After shooting custom guns for the last 10 years I was having a hard time accepting that type of accuracy. This was after I glass bedded the action and the first 1" of the barrel and spent $40.00 on a crisp 2 pound trigger job.

I sent the rifle to my favorite gunsmith to hand lap the factory barrel hoping that would work and I would avoid an expensive re-barrel job. My smith charged me $30.00 to hand lap the barrel.

He said the barrel was typical factory and had a lot of rough patches, but said it lapped out well. Now it was off to the range. Once I got it sighted I shot a 3-group just to see what it would do. It put the 3-shots in a nice .667" group @ 100 yards. After a couple of hours of shooting other rifles I gave it another 3-shot group. This one measured .710" @ 100 yards. BTW I was shooting Fed Premium 180 gr Barnes Triple shock factory ammo.

For a 7.5 pound lightweight hunting rifle with scope, that's alright with me. For less than $75.00 it's a hell of a good shooting hunting rifle.

 

[Gene]

Check this out at Krieger's web site. No fdiscussion of moly, but good cleaning instructions:

http://www.kriegerbarrels.com/RapidCat/c...;CompanyId=1246

 

[Stormrider]

Jeff,
I was reading on the Norma site where they showed pictures of 3 rifle barrels that were sectioned. (Here is the site: http://www.norma.cc/sida/eng/index.html then click on Target, DiamondLine and Barrels retain accuracy...) One barrel has 3700 rounds and is worn badly, another has 7000 rounds and not much wear showing, the 3rd has 10000 rounds. Norma says that 2 of their 6.5X55 barrels got more than twice the number of accurate rounds shooting mollyed bullets than their barrel that shot uncoated bullets.

My question is why this seems to work for them?
How come they did't get the molly build up in front of the chamber that destroyed your barrel?

 

[Jeff In TX]

First I'm no expert, just someone who ruined a new barrel. Being an engineer and one stubborn SOB I couldn't let go until I uncovered the answers and understood what had happened and how to prevent it a second time. I learned a lot along the way. I don't have all the answers. Some folks swear by moly and love the stuff. I saw first hand the damage that could be done with the stuff and enough barrels at Speedy's that were ruined by it to stay clear. I then went on the hunt to find out why.


Like I mentioned in one of the earlier posts, claims can be very narrowly focused. The three photos on the Norma site don't give a lot a detail, only to say it's in front of the chamber. Is it showing the entire throat area, the middle or end portion of the throat or just the lands and grooves after the throat? Also a good cleaning job, specific barrel location and a magnified picture would reveal a lot more information. What is their criteria for loss of accuracy and why?

However if it is the throat section, the barrel with 10000 rounds looks the worst with black build up, almost twice that of the one with the 3700 rounds. But again there is not enough detail or information to gain a true perspective.


There is little doubt in my mind due to lubricant properties of Moly that I think it could help extend the life of the lands and grooves in a barrel. However, one thing that you cannot escape is damage to the throat whether you're shooting moly or uncoated bullets. Over a number of rounds and it's different for each caliber, the excess heat and pressure from the round going off will start to erode and stress crack the throat area. It will also push the throat out. Moly coated bullets are not going to stop this erosion. A .220 swift and a .300 win mags are famous for burning up a barrel in as little as 1000 rounds, while .308 may go 3000 to 6000 rounds. This is one reason you see people re-chambering there barrel to push the throat out. The lands and grooves are usually fine, but the throat section is toast.

Norma is stating that they get longer barrel life due to less friction and pressure, which again I would agree with for prolonging the lands and grooves. Moly is not going to significantly reduce the pressure from the round going off to save the throat area. Meaning the pressure of a normal .308 round going off is around 53,000 PSI. How much lower is a moly coated bullet going to reduce the pressure in the throat section of the barrel that would make it last 3 times longer. Certainly it's going to reduce the pressure to 17,666 PSI's or one third that of 53,000 PSI


As for your real question, I don't really know, not enough detail or information from the picture.

 

[Dzaw]

Not all moly is the same!

Molybdenum disulfide is not chemically neutral, and under such intense pressure and heat, with moisture present (even atmospheric) it can produce sulferic acid. If ever there were a chemical agent that would be bad for even the most corrosion resistant stainless, that's it.

Certain high quality manufacturers have attempted, with varying degrees of success (Some high, as I'm told, unfortunately I have no names ;-(... ) to stabelize the moly without harming its effects.

Others have tried tungsten disulfide. Even slicker than moly, and it can be applied with very exact thickness. I don't know how it's working out, but it sounds promising.

Finally, I still believe that a bore coating is the answer, rather than a bullet coating. I have a propane fired forge and a great deal of abrasives, and so in the near future I will be testing the effects of several different commercially available dry film lubricants and other such treatments to see weather they will offer any resistance to carburization and abrasion. If those tests turn out to be promising, I will run tests by burying tabs of treated and untreated steel in some smokeless powder and lighting it off to see if there's a difference.

If I get something that can protect against all 3 tests better than the bare stainless substrate, I'll be sure to test it in a real rifle barrel. I have a ruger #1 in .243 Win that I want to rebarrel when the factory one is done for, so that one is up for the chop

 

[dbhostler]

Jeff,
Sorry you wrecked a barrel. I've used Necco moly for years and have never had a problem in any caliber but only shoot maybe a thousand rounds a year between a dozen rifles. I rarely use a brush and my "break in" is "patching" a new custom barrel until clean and dry and then burnishing in an alcohol moly mix. Then begins the loading process. I also have a 15X medical grade bore scope but have never seen the moly build up in the throat area you describe. Do you think you could post some pics of this ring or leave a link where some are posted? I also never wax these bullets after coating. Waxing may contribute to the problem you describe.
db

 

[Jeff In TX]

dbholster,

Sorry I have no pics of my barrel. I started this research back in 2001 - 2002ish time frame when I ruined the barrel. When Speedy inspected my barrel we view the bore scope on the TV since he had a video hookup to his bore scope. When Doug Shilen cut out the throat section, we didn't think to take pictures.

Next time I'm up to Speedy's shop I'll ask him if he has some pictures. Lord knows he had enough trashed barrels to look at.

BTW, my moly coated bullets were waxed, but I don't know if the wax played any roll in the destruction of my barrel?

Glad to hear you aren't having any issues.

 

[Mikecr]

Personally, I think barrel makers will tell ya anything. What do they know about barrel life? Or extending barrel life? I think -nothing. Same with accuracy.
If any of them actually knew, we would have barrels from these makers lasting longer than others, or more accurate. Neither is the case. They are just dividing the market, doin the same as any other..

I've read where barrel makers claim their barrels need no breakin. Pure BS. After your barrel is CHAMBERED, it will need breakin. The best way I've seen is with 10shots of Tubbs FinalFinish. Done deal.
Follow up with a few every few hundred and I believe you'll gain significant barrel life.

Soon, someone will hit on a coating/process that helps us all. But it won't be a barrel maker who does this for us.
Eventually, someone will capture, measure, & identify the attributes of a truly accurate barrel. It will be different than the typical barrel produced by our best today. And so it will be difficult to get made in the US.. Maybe a foreign maker like LW might be willing to go out of their way for payin customers.

 

[Dzaw]

Actually, I'm already on that horse...

However, I think you will find that the majority of the best barrel makers out there were shooters FIRST and entrepeneurs after. These guys aren't exactly getting rich on these things. Look at the time, machining, and care that goes into these things, and compare it to the prices they can afford to charge. Good barrels are made by many comppanies, and competition is fierce.

I have a strong, but non traditional background in metallurgy, and understand the modes of barrel failure quite well. There are six major contributing factors to barrel wear, all of which can be mitigated to some degree or another by nothing more than better control of manufacturing (read much more expensive) and improved mettalurgy (also read much more expensive). Preliminary reports on coatings sound very promising that all six can also be addressed in this manner, however, the coating would have to be continuously renewed at some regular interval as an added portion of maintenance.

What I must caution you against, however, is wishing for the ultimate barrel maker. Let's assume, for a moment, that my research into mettalurgical and coating technologies pans out, and best case scenario is realized. Under this assumtion, my new "super tube" would have 10 times current accuracy life of my nearest competiton. In order to make such a "super tube" viable as a product, I would have to charge nearly 20 times the price my nearest competition does. Would you be willing to shell out upwards of $10,000.00 to $20,000.00 US for a barrel? Even if you would, you would be in the vast minority of shooters with the resources, let alone the inclination to do so. Such "super tubes" would price themselves into extinction very quickly. If I had previously hit the powerball, and could afford to take the thousands of dollars of loss on each unit, I might be willing to make a few for friends, but that's about as far as that goes!

Why am I bothering with looking into it at all then? Quite frankly, I have no intention of going into buisiness making barrels. Already too much competition with way more experience at the machining than I've got. However, if I can push the current state of the art forward by even 500 rounds on average, I will have accomplished a great feat indeed!

 

[Stormrider]

Jeff,
Thanks for the reply. I am very curious as to what caused your ruined barrel. I started shooting molly bullets about 2000 rounds ago.

Dzaw,
I am looking forward to hearing how your experiments come out.

 

[goodgrouper]

Interesting post. But I couldn't disagree more. Here's why:

Barrel mfgrs sometimes know what they're doing and sometimes not. Some say breakin, and some say no break-in. Some say phosphor/bronze brush, some say not. Some say moly is good, others say not. Some say ammonia bad, some say it is ok. Some say canted riflings, some say straight. Some say cut rifled, some say buttoned.

Bottom line is experiment on your own and draw your own conclusions.

After doing many, many, many, barrel break-ins, I can say without hesitation that it is ABSOLUTELY necessary. Why? Mikecr has already hit upon part of it. After chambering, there are burrs running perpindicularly to the bore. Also, since no-one can perfectly lap a barrel (or produce one for that matter), there will be burrs and imperfections in the bore. These will eventually get worked out after many firings if no break in is done, but by doing break-in, you get them out one shot at a time because you are running metal to metal contact to burnish them out. Anyone who has properly performed a break-in will actually see this in the process-and this is the fact that the anti breakin crowd cannot explain and will not answer: After "x" amount of shots, the cleaning time was reduced to half or sometimes 1/4.

For instance, I just broke in a custom Kreiger 4 groove 8" twist barrel last week. It coppered the living tar out of the barrel at the muzzle. The copper was was not in steaks like it came from the riflings but was in a wash or patch like look. There was more copper in the wash than what could possibly been "stripped" from the bullet along the lands grooves. It was stuck across the grooves and the lands like it had been vaporized there like Krieger's explanation outlined. So why did it stick there? I don't know, but it remained there for quite some time until I got to the 11th shot cleaning after every shot. Suddenly, the patch of copper no longer formed there. The gun went from cleaning in 6 patches to being spotless in 2. Then I shot 50 shots and cleaned again and when inspecting the muzzle, I could see the copper was laid up upon the lands in a streak manner and none in the grooves. The patch of copper that formed in that one spot the first 11 shots was completely gone. Then I cleaned the gun after those fifty shots and guess what, still only 2 patches to come completely clean. If I had fired those fifty shots without breakin, I would still be out there cleaning that gun!

Of all the things I do to guns, break-in is the most absolutely proof positive thing I can think of. It happens to all barrels custom or factory and it absolutely boggles my mind that there are engineers out there who are supposedly running tests on this and can't admit or figure out why their cleaning time suddenly gets cut in half. /ubbthreads/images/graemlins/confused.gif


As for moly, my own testing on a barrel that had almost 1300 rounds through it before it sprayed projectiles into a shotgun pattern instead of a group, I can say it didn't show much improvement in barrel life. I suspected 1000 to 1200 rounds out of that particular barrel/chambering and only managed to get just a few more than that with moly. And for the little improved barrel life, I got to clean that nasty crap out of my barrel, got to spend extra time or extra money coating my bullets, got to fire an extra 10 to 15 bullets through after cleaning to "season the moly" back in, and got to worry about humidity and moisture getting under the moly and rusting my barrel. Worth it? HELL NO! That is why there has been a HUGE decline in moly users over the last 5 years. It was all the rage and now it is tossed aside like every other fad that has come along.

By the way, there are some solvents that will clean out moly. Bore Tech eliminator gets it out like a garden hose washing out disk brake dust.


As for some of the other points I brought up, here's my thoughts:

Buttoned vs. rifled Either. Just so long as they are done right.

phosphor/bronze brush: Won't hurt a thing if it's clean (no dust or dirt particles in it) and is not short stroked inside the bore. All the way through and all the way back.



Ammonia: Don't leave it in the barrel too long but most manufacturers already tell you that.


Canted rifling: Work good. So does straight. So can polygonal. Suit your fancy but don't get caught up in gimmicks. Peek at BR equipment listings and learn what works and what works better.


3 groove barrels: Don't improve throat life, barrel life, or resist firecracking or pitting. They do however rape bullets very bad (especially thin jacketed vld's), and they seem harder to tune but that could be a result of them raping each bullet's jacket from it.

Now what else......