Telly

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there's a fine line between hobby and mental illnes

Listen to the Craigster, Eldeguello and Stubblejumper, their not steering you wrong.

Of course there are different blends of chrome-moly and S.S., but being "soft" is not one of their virtues. I've heard that the steel in Lothar barrels is "hard" and doesn't machine like leaded steel, which is true, but it will flame cut just like any steel it you shoot it till it glows red. What is soft or hard to a machinist and their meaning of the words doesn't belong to the outside world. The words have special meanings just like doctor or lawyer 'ese.

I have a Rem 700 in 17 Rem that is so rough for the first half of the barrel it's difficult to push a cleaning rod through it with a patch on it. I use a nylon brush to get the cleaning process started. The rifle still shoots 1/2" to 3/4" with molyed Rem or Horn 25's. I put over 3000 through it and I bought it used. Now, would you say that barrel is "soft"? Not me. I wish it would quit shooting so "good" so I could get my other barrel on it.

Chic Worthing

quote:

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Originally posted by MAKATAK:
...not to mention misinformation, disinformation, complete prevarication, larceny, libel, slander, calumny, scandal, defamation, aspersion, malicious falsehoods, and character assasination....

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This makes me think of "Alice's Restaurant". Set it to a tune & it could be another verse!

The "warm barrrels wear out" goes back to machine guns in WW1 and WW2. Where, of course, in the heat of battle, they were sometimes fired until they were literally red hot.

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Doug Humbarger
NRA Life member

I posted in that thread:

African Hunter, African Perspectives page III, Vol 7 #6, Lessons Learned

Rifle Lessons learned from the Zimbabwe Professional Hunter Proficiency Exam
by Don Heath

"Interarms Mk X. Apart from the fact that the barrels are soft and wear out vey quickly, these are intrinsically sound rifles that are simply shoddiy put together. They are famed for springing the magazine floor plate open and dumping the contents on the firers feet. Never seen one that wouldn't feed reliably though, and with a little bit of gun smithing to make the safety catch more positive (it is also on the "wrong" side) so tht is doesn't get accidentally swept on as the bolt is opened (or accidentally knocked off in the bush) and the stock properly bedded to cure the "magazine dump" they can be made into very workable rifles. They are though, very definitely rifles that you take first to your gunsmith and only them to the bush as the two students at Rifa discovered."

The Zastava rifles are just arriving in the US under the Charles Daly name, but they have been here before and other places as Mark Xs.

Also I commented on Remington barrels elsewhere. I had a .416 RM rifle from the Custom Shop that fouled after a handful of shots. I sent it to Jim Brockman for smoothing and hardening. Jim commented at the time that most Remington barrels he is asked to do something about are rough. I have Shilen and air-gauged Douglass XX barrels that are smooth, don't foul and clean-up quickly and easily. Ditto with my Steyr rifles.

Rifles made on a large scale by American factories are made to sell at price points as low as possible. The barrels are one element. Many, many hunters shoot less than one box of ammo a year. Those barrels will work for that.

On my next project rifle I plan on following Ray's recommendation and using a Lothar Walther barrel so I can at least get some direct experience.

I used rifle data books for my target rifles, so I knew how many rounds of what I had fired through them, and what was happening to accuracy. I didn't have any trouble running 80 rounds through a .308 or about 30 through a .30-.338 pretty quickly. Of course those were top of the line custom barrels.

Now a days I worry mostly about one shot groups on game, but I still keep track of rounds fired.

jim dodd

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"if you are to busy to
hunt, you are too busy."

But I did run across some interesting facts about heat years ago and I think I can remember the figures within a few 100 degrees. First, gunpowder burns at about 4,500 degrees. Steel melts at about 2,500.
(Don't quote me on these temps but I believe the ratio is about right.) Anyway, you get the idea...heat CAN be a dangerous thing in firearms. This said, I think there are probably only two ways to achieve enough heat inside a barrel to do serious harm. One, is to have a fully automatic weapon. Everyone knows you can burn a machinegun barrel into scrap iron very quickly. Two, are vastly overbore cartridges. Cartridges that are burning an extra 20 - 30 grains of powder in some wild attempt to squeeze an extra 100 fps are also creating a firestorm inside the barrel that shortens barrel life tremendously.

Point being, I don't think anyone with a bore efficient rifle cartridge needs to worry much about the barrel being "soft/hard."

Different makers use different alloys to give better *wear*. Hardness has little to do with erosive wear, the alloys do.

Heat and cleaning rods wear out the majority of barrels. The ratio in my shop over the past 35 years is about nine worn out from improper cleaning and one worn out by shooting. Of course most barrels are replaced because the owner wants something else, not because the barrel is bad.

Let me beg to differ a bit on the rapid-shooting, hot barrel wear theory.

The metal in the barrel starts out at, say 70 degrees F. After the first shot, the entire barrel is warmer, but in particular the area of the throat, which has had virtually all of the powder burned as it passes through it, unlike the muzzle, where virtually no powder is burned. With each succeeding shot, that area gets hotter, but cool slightly between shots. At some point, if shots are closely enough spaced, the metal of the throat will be warm enough that the next shot raises its temperature above the melting point, and a tiny skim of metal is burned away. It's hard to say at what point this occurs, and is bound to vary from gun to gun and caliber to caliber, but I believe that it occurs with large-for-caliber cases when several shots are taken in less than a minute or so.

On the other hand, I think most shooters will NEVER experience the reality of a "shot out" barrel, and I agree with the fellow who said that most barrels are replaced because the owner wants something else, not because they're worn out.

I believe that most actual "shot out" barrels are a result of either a bad batch of steel, a relatively large number of shots of a seriously overbore cartride and/or poor cartridge case design combination(6mm Rem is not as hard on barrels as the .243 it is reported), or a poor choice of steel alloy to begin with as in some foreign barrels and possibly some cheaper US ones.

Since the peak burn temperature of smokeless powder is substantially above the melting point of steel and that is combined with high pressures I believe it is primarily the number of such events(shots) that occur not the frequency of them.

To bolster my view, I refer you to Precision Shooting, April, 2002, article called "Benchrest Basic Training" by Frank L. Murphy:

"It's an old chestnut in the shooter's storehouse of sacred lore: don't shoot too fast and overheat your barrel or you'll wash out the throat. .........But there isn't much risk of overheating a barrel enough to do any special damage during any normal kind of varmint hunting or target shooting......Yes, the barrel gets hot, but that relatively minor degree of heating has little to do with shortening barrel life.

The damage to the throat of the barrel is due in small part to mechnical wear, and in large part to the effects of heat, occurring during the very brief periiod of very high temperature that occurs during the peak pressure as the powder charge burns. Heating and cooling are brief but intense, and damage the surface of the bore to promote corrosion, producing what has been called "firecracking." Throught the bore scope, it looks like the cracked mud in the bottom of a dried-out mud puddle. IT MAKES LITTLE DIFFFERENCE WHETHER THE BARREL STARTS OUT AT 70 DEGREES OR 270, BECAUSE THE DAMAGE IS DONE DURING THE BRIEF PERIOD OF PEAK PRESSURE AND TEMPERATURE, NOT DURING THE MUCH LONGER MOMENTS AFTER THE BULLET PASSES AND BETWEEN SHOTS, WHEN THE BARREL IS COOL.." (Emphasis mine, not the author's)

continuing:

"I went over this problem with Woody Woodall, who is president and CEO of Lothar Walther Precision Tools, the barrel maker. He does not feel that rapid fire, as practiced by BR shooters and varmint hunters makes much difference to the life of the throat, and points out a number of other factors that do contribute to rapid throat erosion. First is the choice of steel: 416 SS is easy to machine but not necessarily the best for resisting throat eroision. Second is the throat angle. Shallower throats, often chosen for accuracy, lenghten faster as they erode. Third is the load, with large charges of slow burning powder supplying the most heat and doing the most damage." End PS quoted text.

With all due respect, I will fall in line with Woody Woodall who knows more about barrels than I do or ever will, and likely more than you do.

[This message has been edited by Robgunbuilder (edited 05-14-2002).]

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Originally posted by Robgunbuilder:
I believe that the case volume to bullet diameter ration is the cause. This is why barrels inn certain calibers i.e. 30-06, 270 win.etc seem to last forever. -Rob

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In other words, OVERBORE cartridges eat barrels...which is something we've all seen and witnessed for 40 years. Certainly it's the flaming gasses that eat up barrels and so the less powder/bore diameter we have roaring around inside there are 4,000' the better off a barrel is. In other words, efficient cartridge barrels live longer.
No mystery. No magic.

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A well placed bullet is worth 1,000 ft/lbs of energy.

Couple heat with the abrasive effects of all those little particles of unburned powder rattling around and you have throat erosion. You might liken it to a VERY FAST oxidation process, RUSTING if you will.

The same thing that happens when you get after a piece of metal with a oxy/acetylene torch. nce you get the metal heated up to a certain temp you can shut off the acetylene because it is the oxygen that does the cutting.

Gunpowder has oxidizers in it otherwise it wouldn't do so well in a confined space. The momentary intense heat, which is a type of plasma as mentioned above, coupled with the abrasiveness of the powder particles, the friction of the bullet passing over superheated metal and the reactive nature of steel with oxygen and you have an etching of the barrel. How long a barrel lasts depends on the type of metal in the barrel, the amount and duration of the flame front, the initial vs the later temp of the barrel, the amount of powder producing the flame front, the size of the bore, the type of bullet used and a bunch of other factors that for the most part can't be measured in the normal course of events.

Stainless steel is a non-reactive metal in that it has to be melted I can't be cut with oxy/acetylene the normal way a piece of steel can be cut. Yes you can use a plasma cutter. So it lasts a little longer than ChromeMoly, but that is a gigantic battle ground for another thread.

Anyone notice that the barrel heats at different points depending on the relative speed of the powder? My bigger bores have their hot spots 6" to 12" in front of the chamber depending on the bore size, the bullet weight and the type of powder I use. Most of the larger 22 cals, 6mm and 25 cal's are usually 3" to 6" and 17 or 223 us just in front of the chamber. I haven't done a quasi-scientific test on any rifle yet just noted where the warm spot is when I am in the developmental stage with a new caliber but that queston is in the back of my mind and I have two barrels coming that such a test will be included while load development commences.

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Doug Humbarger
NRA Life member