What really causes a barrel to wear out...

J E Custom said:

Most of the time.
When someone brings a rifle to be re barreled it is quite easy to see the abuse with a bore scope and a head space gauge especially when you hear the round count.

I often find bolt lug set back, fire cracking and other signs of over pressure loads and erosion from primer failure. I was once afflicted
with the hot load sickness and it brought me nothing but problems and short barrel life. After seeing the errors of my ways I have not destroyed a barrel sense.

Just my experience with barrel life. There can be much more usage in a good barrel if all of the known reasons for poor life are avoided.

J E CUSTOM

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Aye Sir! I happen to agree with you. As always, thanks for sharing your insight. Nothing beats real world experience.

In addition to your use and abuse statement, along the same lines, I read an article of improper barrel/chamber cleaning but I cannot seem to find the article. But in either case, it still points out to the "NUT" behind the trigger.

FEENIX said:

Aye Sir! I happen to agree with you. As always, thanks for sharing your insight. Nothing beats real world experience.

In addition to your use and abuse statement, along the same lines, I read an article of improper barrel/chamber cleaning but I cannot seem to find the article. But in either case, it still points out to the "NUT" behind the trigger.

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Proper cleaning has been one of the most notable things to me that extend barrel life.

I go the extra mile by sweeping the bore with a bore snake between shots when I am hunting. it pushes the carbon fouling out of the bore that can abrade the barrel when firing a bullet through it. A dry patch will do it but it is not practical in the field so I use a bore snake.

In addition to not doing the things I/we know that Is bad for the barrel, cleaning compliments the reduction of barrel wear.

J E CUSTOM

The OP certainly does not seem to understand the nature of high temperature cyclic oxidation. Some materials like 300 series form a tenacious oxide layer that holds up well, so long as exposure is not cyclic. For cyclic oxidation, materials that have thin oxide layers and low expansion coeficients do better. As the average temperature gets higher one invariably moves to nickel as the base alloy and starts adding other elements like Al due to the nature of the oxide that it produces. Up at the tippy top of the scale are materials like Haynes 214.

The other thing of note is that at the top end of material limits, a shift up in temperature of 50c could reduce the local mechanical properties by 50% or more and catastrophically reduce service life.

We really dont spend a whole lot on our barrels and so they have to be made from something relatively cheap, which can be processed efficiently on the sort of equipment used for barrel making, especially drilling and the rifling process. That pretty much means 416 stainless steel and Chrome Moly for most of us. Perhaps in some cases the military may use something better in high rate of fire applications like on the A10 and other high asset value applications. But for man carried stuff im sure the disposable mentality applies.

Isn't the answer obvious? Shooting wears the barrel out.

Jesus Christ guys, I came across an interesting video that gave a theory about why some barrels are accurate with several inches of rifling gone while others are "shot out" after only 6-700 rounds with not as much rifling worn out. I thought it would spark good discussion and thinking about the culprits in degrading accuracy. Instead it's only brought out personal attacks about my intelligence and smart *** remarks.
Don't worry, I'll never post anything that challenges your collective awesomeness and full understanding again.

Mods: please delete this entire thread

They are not insulting you. But we do see things very differently than the author of the video sees it.
Nothing against you. We all can learn here.

It actually spurs discussion, that is good

I watched a "Torture test" of some AR-15 rifles on youtube. I think something like 5000 rounds fired through each of them with periodic accuracy testing. At the end they basically had no rifling left and only shot slightly worse than at the beginning....

Wait, there's the catch. None of the rifles were better than 2.5MOA when brand new and thats at a close distance 50-100 yards. If your barrel is so crap to begin with, how are you ever to tell any degradation ? How would you know if you were shooting a smoothbore instead of a rifle, if the shooting distance is so short that you dont even give the bullet a chance to tumble ?

I suspect that rifles that are still shooting well with a throat that has been shot out to 12" long are most likely shooting light for twist bullets that are able to stabilize in the remaining rifling and are still going fast enough, even if there is some blow by in the first part of the bore. Trying a rifle in this state with a bullet that is close to maximum weight for twist will probably show a completely different result.

I've worn out a few barrels.

I ruined one great 22-250 barrel with just under 2800 rounds thru it by using a second rate bore guide, cutting a nice groove in the throat at 6 o'clock.

Just replaced a shot out barrel on my 308, 85oo rounds there abouts. First 7 inches from the chamber were smooth, and the last two inches near the muzzle showed significant gas erosion. Oddly, the thing still shot moa.

On the 300, if you download to 308 velocities it will last as long as a 308. Friction and heat induced by combustion take a tremandous toll on barrels. Improper cleaning ruins the rest.

odoylerules said:

Jesus Christ guys, I came across an interesting video that gave a theory about why some barrels are accurate with several inches of rifling gone while others are "shot out" after only 6-700 rounds with not as much rifling worn out. I thought it would spark good discussion and thinking about the culprits in degrading accuracy. Instead it's only brought out personal attacks about my intelligence and smart --- remarks.
Don't worry, I'll never post anything that challenges your collective awesomeness and full understanding again.

Mods: please delete this entire thread

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I think you are misunderstanding the remarks that call out the video for being directed at you? The comments are not an attack at you at all. The value is that sharing it is important for the purpose of pointing out the deficiencies in what is being offered in the video.

The peer review process can be flawed when there is confirmation bias and political agenda on the committee, but this is how the world works. There are very few meritocracies left in the world to insure qualifications before being granted a vote in technical research. The internet was always been a lost cause. The only filter we have here is each other and the mods. The whole idea is to put your ideas and observations on the table. Don't be surprised if someone has already been there... Sometimes, we do find that the world is really round too...

I for one hope you don't stop posting and realize that "you" are not that "video" and that the video needed the criticism in some places, and even then the poster of that video is still entitled to his opinions and observations. It is just as valuable to refute something that isn't true as it is to share something that has value.

The more his theory checks out with repeatable results from other researchers, the better, but in many places he lacks the background and many of us here are qualified to be his critics. We are all here to share and learn, so don't take it the wrong way. We just pointed out the guy in the video was way off in much of what he was saying from an engineering and physics view. There are many who can contribute without a PhD in physics, and at the same time, some who clutter the internet with noise. Somewhere in there we can sort things out if we remain calm.

J E Custom said:

Proper cleaning has been one of the most notable things to me that extend barrel life.

I go the extra mile by sweeping the bore with a bore snake between shots when I am hunting. it pushes the carbon fouling out of the bore that can abrade the barrel when firing a bullet through it. A dry patch will do it but it is not practical in the field so I use a bore snake.

In addition to not doing the things I/we know that Is bad for the barrel, cleaning compliments the reduction of barrel wear.

J E CUSTOM

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How is your next cold bore shot after the bore snake? I HBN my bore and bullets so I wonder how this would affect the bore condition.

tbrice23 said:

How is your next cold bore shot after the bore snake? I HBN my bore and bullets so I wonder how this would affect the bore condition.

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It has no effect on accuracy, It mainly sweeps out any powder debris and carbon that could contribute wear to the bore. I use no solvent or oil on the bore snake.

If you don't believe how much it removes, Fire one round through your rifle and then dry patch it with something under the muzzle to catch anything that doesn't cling to the patch and look at both.

Anything left in the bore becomes a potential abrasive when a fired.

At one time I used molly in my barrels and on my bullets, but could never tell when the bore was really clean so I stopped using anything in the bore.

J E CUSTOM

J E Custom said:

If you don't believe how much it removes,

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I have bore snakes in a few calibers, I see the cloud of powder molecules that comes out. Just wondering if the next shot is still zeroed.
The brush might remove the hbn base in my barrels.

RegionRat said:

It is just as valuable to refute something that isn't true as it is to share something that has value.

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One of the best parts of a post I have seen. This is signature material!