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Old March 8, 2014, 10:09 AM   #26
Unlicensed Dremel
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"The bore is going to be just as toasty either way. "

Not necessarily. The same amount of heat is generated, true. But the rate of dissipation relative to heat created will determine net bore temp. Depends on many factors.

"It is possible, however, that the greater amount of metal in the fat barrel will draw heat from the surface of the bore faster than the smaller amount of metal in the thin barrel will."

Yes, exactly!

"But, on the other hand, the thin barrel may shed the heat to the air faster than the fat barrel will."

No. The fat barrel has more surface area (contact area with the ambient air), and thus can dissipate at a faster rate.
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Old March 8, 2014, 10:36 AM   #27
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People who shoot unaltered factory commercial actions with either original factory or aftermarket barrels typically experience point of bullet impact changing as the barrel heats up regardless of barrel stiffness. The more stiff the barrel is, the less that point of bullet impact changes.

People who shoot factory commercial or aftermarket custom actions with squared up receiver faces and aftermarket barrels properly fit typically experience no point of bullet impact changing as the barrel heats up. Doesn't matter how stiff the barrel is.

People have been shooting .308 Win. chambered 30" long "pencil thin" skinny barrels in the 4 to 5 pound range in properly trued actions for long range competition since the late 1950's. A typical barrel profile is Kreiger's #16 light Palma barrel listed in:

http://www.kriegerbarrels.com/Contours-c1246-wp3382.htm

My first Palma rifle's heavy barrel contour was the same as Kreiger's #10, its second light weight barrel was the same as the #16. Both shot equally accurate at long range and never walked shot impact as a 25 to 30 shot string was fired in half as many minutes starting with a cold barrel.

Every unaltered commercial Winchester 70 or Remington 40X centerfire match rifle I've shot, all with heavy bull barrels, walked their shot impact as they heated up. Didn't matter if they were .30-06, .308 Win, 28 or 30 caliber magnums. Epoxy bedding their receivers and totally free floating their barrels didn't help at all. Putting a pressure pad under the barrel at their stock's fore end tip made all of them shoot worse.

Unless one's shot such a properly built rifle well enough to observe point of bullet impact never changing as the barrel heats up, I believe they think and claim all rifles do that. They'll never observe the rifle and its barrel's accuracy does not change as the barrel heats up. The range of barrel temperature change isn't enough to cause a significant difference in how rigid or stiff it is.

But all of this will be difficult for some folks to grasp.
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Old March 8, 2014, 11:08 AM   #28
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Dremel, I see your points, but regarding the shed of heat from the thin barrel versus that of the fat barrel, I'm not sure you are correct. Consider that the thin barrel has less surface area, but it will have a higher surface temperature. I'm thinking that the higher temperature will cause a more rapid heat loss than the lower surface temperature of the fat barrel. Once upon a time, many years ago when I was a working Process Engineer at an oil company, I actually used to do calculations of heat loss, surface temps, and temperature gradients across metal pipe walls and even smoke stacks. That's out of my skill set now. And I will admit that there were many times when my preconceived notions of the final answer were 180 degrees from the right answer when I finally finished the study.

And Bart, sometimes things are not so difficult to grasp as they are to accept. And I have to wonder why you would have a heavy barrel on any rifle, if it matters not to accuracy.
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Old March 8, 2014, 11:50 AM   #29
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603, heavier rifles (barrels?) move slower around their aiming area when hand held. They also move less in recoil during the time the bullet goes down the barrel. They're easier to shoot accurately than light ones. This is why service rifle shooters started using heavier barrels in their M1 and M14 rifles; the skinny barrels shot just as accurate but the heavier ones produced better scores.

The physics behind this should be easy to figure out.
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Old March 8, 2014, 12:22 PM   #30
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Well, that certainly does make sense, and I have always shot heavier barreled rifles better than light rifles with thin barrels.

And I can't really disagree with your premise that thin rifle barrels can be as accurate as fat barreled rifles, at least in theory. If a fellow had high dollar custom barrels, both light and heavy, I would expect them to be equally accurate. But in the over-the-counter world that most of us live in, and where we buy non-custom rifles, I would be quite surprised to find that thin barrel rifles shot as well as heavy barreled rifles. I believe that a heavy barrel on a standard non-custom rifle (Remington, Ruger, Savage, whatever) will be marginally more accurate and I would expect that to be due to the more forgiving nature of a heavy barrel in a less than great stock. I can't prove the above with either math or actual experience, but I do believe it to be true.
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Old March 8, 2014, 01:28 PM   #31
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All that is being said here,about heat,ect,ect is true. The point that is being overlooked is-- A skinny barrel fired slow allowed to cool is every bit as accurate as a fat barrel. The points being stated here are the side affects of a heavy barrel.
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Old March 8, 2014, 01:59 PM   #32
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First, let's get one thing out of the way. The "bull" barrel has nothing to do with the male bovine; it is named for Freeman Bull, an employee of Springfield Armory, who after having fired a whole lot of ammunition out of a whole lot of experimental barrels, concluded that a heavy barrel gave more consistent accuracy over time than any other type.

Today, with far better barrel making techniques than were available even to Springfield in that era, we find that heavy barrels are not always the key to accuracy, that there are other factors, some of which have been touched on. But the light barrel that shoots sub-MOA all day is still the exception, and the really long range shooters don't use buggy whip barrels.

Jim
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Old March 8, 2014, 03:35 PM   #33
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.22 bull barrels as used in small bore competition also tend to give the extra weight needed to reduce "weaving" and increase stability.

And that's a very interesting historical fact about the origin of "Bull barrel," Jim. Yet another word that has become a "proprietary eponym" into our language along the same lines as "browning (any self-loading pistol)," "winchester, (any repeating rifle)" "coke, (any cola drink)" 'kleenex, (any tissue)" "aspirin," etc.

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Old March 8, 2014, 03:40 PM   #34
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Jim, buggy whip barrels are the norm in Palma rifles as 30 to 32 inch ones are needed to shoot 150 grain bullets from .308 cases fast enough to remain supersonic through 1000 yards in cold weather and keep rifle weight under the 6.5 kg limit (about 14.4 pounds) yet be light enough to manage shooting them slung up from prone. They shoot as accurate as really heavy and thick long range benchrest barrels; all shots under 6 to 7 inches centered about point of aim in good conditions.

And for some folks, a 6 kg rifle weight's the limit they can shoot accurate enough to win.
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Last edited by Bart B.; March 8, 2014 at 07:31 PM.
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Old March 9, 2014, 02:38 PM   #35
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When Leslie Edelman dropped the Herters line, they were selling .308 threaded Mauser 98 barrels for (ready for this?) $9.95. They were 22 inches and only a tad over 1/2 inch at the muzzle. I bought several and sold all but one. One of my good friends bought one and had it put on a VZ-24 action. That rifle, with GI Match ammo, shot sub MOA and would do it all day. Needless to say, the one I kept shot OK but nothing spectacular; the others were the same. The barrels looked the same, and they came from the same factory, but one rifle was somehow different. And mine was also put on a VZ-24 action by the same gunsmith who did the super-accurate rifle. Go figure.

Jim
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Old March 10, 2014, 08:40 PM   #36
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Dremel, a perfect thin barrel and a perfect bull barrel will be equally accurate, hot or cold. The problem is there are very few "perfect barrels." Bull is a tad bit more forgiving of imperfection.
Unless things have recently changed, a thin barrel rifle holds the 1k world record for group.
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Old March 13, 2014, 01:48 PM   #37
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And how much time passed between shots for that group?

Are there ANY in fact "perfect" barrels - you implied that they're rare, but not that they're non-existent. You *sure* they're not non-existent?
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