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Old August 19, 2011, 11:29 PM   #1
Darksith
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Question: Gun Powder and your barrel?

My question is this.

What damages/causes wear on your barrel when thinking about shooting. Is it the gun powder causing corrosion and other things, or is it the pressure build up that puts wear and tear on your barrel, or is it simply the bullet travelling down your barrel?

I am working on a load for my 30-06 and I am relatively new to reloading (3rd year now). I have gotten to the max load for the bullet I am shooting, and have for curiosity sake gone 1 grain over max just to see if I have any troubles with it. Max load is based on pressure correct? So going over max load means you are exceeding recommended pressure, but is that a safety thing more so than a "will cause excessive wear and tear on your barrel" thing? Im not looking to push past recommended max load, Im just curious.

example
If Im loading a 150g bullet I can put more grains in my shell than when Im reloading a 180g according to my book. So is shooting a bullet that has more grains of powder going to wear out my barrel quicker than shooting a different bullet with less powder but greater pressure build up?
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Old August 20, 2011, 01:09 AM   #2
Jim243
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The short answer to all your questions is "Yes". Each element will have an effect on the metal within your barrel. All shots, high pressure, low pressure, median pressure will have some effect.

The higher the pressure (more gunpowder) the faster the barrel will be used up. Unless your barrel is made of Titainium (not likely too expensive)

The heavier the bullet the faster the effect, but this is a double edge sword, the lighter the bullet the faster it will travel down the barrel and will have even more of an effect.

Depending on the quality of the "steel" that is used in making your barrel and the amount of carbon used in making that steel will have an effect on how fast or slow the rifling in the barrel is worn down.

As an example a 65 grain 243 bullet (wildcat round) shot out at 3,800 feet per second will require a larger charge of powder so the powder and fast speed of the bullet will wear out the barrel faster than say a 95 grain bullet with a median to low charge will. How ever a 105 grain bullet will build up more pressure on a "hot" load and produce more friction on the throat and rifling than a faster 95 grain bullet.

It's a trade off, more powder higher chemical action on the barrel, heavier bullet more friction on the barrel.

Now the hard part, some calibers like the 243 are considered wildcat rounds which will erode the barrel faster giving it a life of say 800 rounds before it loses accuracy. If I drop the speed of the bullet to say 2,600 feet per second I can get maybe 1,500 shots off before the barrel need to be replace to keep the same level of accuracy. So calibers like the .308 or 30-30 will last 5,000 rounds before needing to be replace the barrel.

So rule of thumb is to keep your loads down to what is most accurate in your rifle and no higher in powder than what is required for that accuracy.

Which is a good rule to follow in life, stay cool under the collar, keep your blood pressure down and live a good long life.

Jim
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Old August 20, 2011, 08:35 AM   #3
rg1
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Your barrel will only last 6 seconds! Here's a very interesting article:
http://bulletin.accurateshooter.com/...s-barrel-life/
I've read that powder type can effect barrel life. You will get some erosion from the powder granules but also the flame temperature of the powder will cause some difference. Overheating of the barrel shooting fast will make a difference. But most of the info you'll find will say that improper cleaning of the barrel will cause more wear and ruin more barrels than anything else. Experts say to use a proper fitting bore guide for your cleaning rod, a coated one piece rod, and cleaning from the chamber end if possible. And as mentioned some calibers just burn out barrels faster than others.

Last edited by rg1; August 20, 2011 at 08:51 AM.
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Old August 20, 2011, 08:40 AM   #4
Uncle Buck
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Exceed the maximum pressure and you will not have to worry about the barrel much longer. There is a reason for max pressure. Your barrel will only contain just so much of it before it blows.

I think I understand what you are trying to do/figure out, but be very careful. A ruptured barrel puts you and anyone standing next to you at risk.
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Old August 20, 2011, 07:13 PM   #5
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Kind of like humans. The minute you are born you start dieing.
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Old August 20, 2011, 10:18 PM   #6
T. O'Heir
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"...What damages/causes wear on your barrel..." Repeatedly shooting it. You're lighting a hot fire in it and pushing a bullet through the barrel. Both cause wear, but in most cases, you'll never wear out a barrel in your life time. Unless you're a target shooter. Moreso for the bench rest guys. Different accuracy requirements than a hunter.
One grain over max won't make much difference. However, it's not something to play with.
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Old August 21, 2011, 01:13 AM   #7
Jim243
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Quote:
One grain over max won't make much difference
You mean 1/10 grain not one grain, Right?

Jim
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Old August 21, 2011, 10:24 AM   #8
snuffy
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darksith, two of them there always is!

Well everybody has danced around the real answer. The part or area of the barrel that causes the barrel to become inaccurate is the throat, also called the leade. It's that part directly in front of the chamber, a short taper from the outside diameter of the bullet to the bore diameter. In a .308 barrel, the outside diameter of the bullet, .308 has to be tapered down to .300, or the bore diameter.

I don't like to call it "wearing out" the barrel. Barrels that are "shot out" often have very nice sharp rifling ahead of the burned out throat. A trick that's often used by gunsmiths is to SET BACK a barrel. By that I mean shorten the barrel from the chamber end, by cutting about an inch off, then re-threading and re-chambering the breech area. This eliminates the burned out throat. They do this because the barrel when new was a very accurate tube.

The throat is burned by the brief extreme heat of the burning powder. Some say it's caused to some extent by abrasion of the powder granules. If you WANT to make a barrel go bad quickly, shoot a lot very fast without letting the barrel cool.

The tip rg1 made about cleaning, is spot on! More barrels have been ruined by improper cleaning than by shooting too fast. Cleaning from the breech with a good bore guide is the best way. If you must clean from the muzzle, use a good tapered brass guide. It centers the rod so it doesn't contact the rifling grooves at the all important crown of the muzzle. Damaged crowns are the number one reason for rifles shooting bad groups or causing flyers from an otherwise good group.
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Old August 21, 2011, 05:16 PM   #9
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thanks, good to know.
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Old August 21, 2011, 07:54 PM   #10
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You cannot underestimate the damage you can cause to a barrel from excess heat.
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Old August 21, 2011, 08:47 PM   #11
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As Snuffy said, the throat is what goes, from heat. Nevertheless, there have been certain high velocity and high pressure cartridges that are infamous barrel burners. .264 Winchester Magnum, .220 Swift were two (varmint shooting).
In your case, with a 30-06, if you use milder loads in your hand loading, your barrel will last longer. However, if you do not shoot other than hunting, your barrel will last a long time anyway. Hunters usually do not shoot enough to wear a barrel out.
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Old August 21, 2011, 09:05 PM   #12
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To address a misconception...Max loads are usually written as "max recomended loads."
All the factors for pressure are taken into consideration, but are mostly unknowns as far as YOUR equipment is concerned. When someone, either one of the factories, or another reloader, gives you an opinion on a particular load, it's a given that if you use it, you will drop back some, then work it up.
Think of this..Your gun is different ( longer/shorter throat, tighter/looser tube, longer/shorter barrel, and longer/tighter chamber)
Now to get even scarier...Your powder is probably a different lot, as well as your cases, primers, and bullets! The other shooter, may not mention the COAL.
To continue...Your scale MAY not be EXACTLY the same as the other guy. Yes, it's true...a grain MAY not be a grain.
My main point is that if you load WAY too hot, your gun MAY not blow up. The safety factor is based on the strength of the CASE, not the gun. Of course, I'm not talking about Damascus-steel, or junk. I'm saying the you are using quality componants
You load 62gr of Bullseye in an '06 with a 180gr bullet and YES....you will exceed the strength of the steel, or SOME part of the gun, but a little extra powder, will prolly not cause that much trouble, tho' you may ruin the gun.
Dang...gotta go to work. I'll be back.
Have fun,
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Old August 21, 2011, 11:14 PM   #13
Darksith
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I have worked up to the recommended max, and then gone past knowing that each variable is different. I just wanted to know if it was not a smart move to go past max not b/c of safety, but rather for the longevity of my rifles barrel. I do want my loads to be moving as fast as possible so I have the most hitting power, without sacrificing accuracy of course, and I want my bullet traveling as flat as possible for an '06 so I can think about taking a bit farther shot comfortably. I do shoot about 50-100 rounds a year with my gun at the range. Mostly to develop my loads for different bullets, which also gives me practice at reloading.

My primers were flattening a bit at or above recommended max load, but some did not so I don't think Im being unsafe, but that being said Im not going to push the envelope, I was simply curious.
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Old August 22, 2011, 09:42 AM   #14
Nevmavrick
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To answer your question may be difficult, because you shoot so little that it'll take a couple generations to reach sufficient wear to be measurable.
If someone were to shoot more, so the barrel got hotter, then it would be easier to demonstrate a difference.
If you put more powder through, with equal pressure, you prolly will cause more wear, as the biggest wear-factor would be the heat(that's prolly more opinion, than fact)
Also, IMHO, if you use a double-base powder, you will prolly cause more heat, hence wear, pressure and powder-weight being equal.
Most of this would be hard to prove, therefor highly debatable. That's OK, I get involved in a lot of arg....uh, debates. lol
Have fun,
Gene
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Old August 22, 2011, 09:54 AM   #15
dahermit
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Get a bore scope and look at the throat of your rifle while it is still new (few rounds fired). Then after about 500 or more, look at the throat with the bore scope again...you will have your answer.
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