Are fluted Barrels better?
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Art Eatman
Staff in Memoriam
The theory is that the barrel will be stiffer without being heavier; and, the greater surface area allows faster radiation cooling during the firing of a string of shots.
Do a search for "Gale McMillan + fluted barrels" or some variant thereof. He wuz agin 'em.
FWIW, Art
Do a search for "Gale McMillan + fluted barrels" or some variant thereof. He wuz agin 'em.
FWIW, Art
swifter...
New member
Best effect is on sales...
It does lighten the barrel and sacrifices little stiffness in the process. In other words, while it ain't as stiff as it was, its stiffer than a lighter barrel would be...
My favorite riflesmith swears it'll improve accuracy, but I'm damned if I see how.
As far as cooling goes, which is another argument, you can improve heat transfer by painting the tube flat black, I understand.
It does lighten the barrel and sacrifices little stiffness in the process. In other words, while it ain't as stiff as it was, its stiffer than a lighter barrel would be...
My favorite riflesmith swears it'll improve accuracy, but I'm damned if I see how.
As far as cooling goes, which is another argument, you can improve heat transfer by painting the tube flat black, I understand.
Badger Arms
New member
Stiffer barrel for the weight. Better cooling. Everything else is simply secondary. For those who disagree, use a bit of common sense. More surface area WILL provide quicker cooling. Arguing this point is like arguing that the Earth is Flat.
Whether or not the increase in stiffness and drop in weight justifies the cost is another story. My AR-15 Shorty is fluted, but that's the only gun so treated.
Whether or not the increase in stiffness and drop in weight justifies the cost is another story. My AR-15 Shorty is fluted, but that's the only gun so treated.
Hmmm ... I'm with Badger on the cooling part ... no arguing that fluted will cool faster. As far as "all else is secondary" and the questionable claim of better accuracy ... I'll throw this thought out there for fun:
Every barreled system will have a certain vibrational characteristic that is related to the ratio of stiffness to mass. "Stiffer for the same weight" means that we will change this ratio. I'm not sure that this is necessarily good, but it might explain why there is at least some anecdotal evidence that fluted is more accurate ... maybe it was ... on a rifle that was having vibrational problems in its unfluted state. Just a thought.
As for flat black ... radiant heat really becomes important at higher temperatures, so I guess that might help if you go full auto, but otherwise I'd take the fluted option if improved cooling is what you are looking for.
Saands
Every barreled system will have a certain vibrational characteristic that is related to the ratio of stiffness to mass. "Stiffer for the same weight" means that we will change this ratio. I'm not sure that this is necessarily good, but it might explain why there is at least some anecdotal evidence that fluted is more accurate ... maybe it was ... on a rifle that was having vibrational problems in its unfluted state. Just a thought.
As for flat black ... radiant heat really becomes important at higher temperatures, so I guess that might help if you go full auto, but otherwise I'd take the fluted option if improved cooling is what you are looking for.
Saands
I was advised On my VMatch 16 inch to pass on the fluting. It is already a heavy barrel and will disapate heat slowly.
Besides, it is a SA and not FA and I can't pull the trigger that fast. As for any added accuracy, IMHO how can adding a heavy barrel, then taking wieght off by fluting it help accuracy?
Now if they could make a barrel like (.) You know, sorta like() then I could see less whip
Besides, it is a SA and not FA and I can't pull the trigger that fast. As for any added accuracy, IMHO how can adding a heavy barrel, then taking wieght off by fluting it help accuracy?
Now if they could make a barrel like (.) You know, sorta like() then I could see less whip
Double Naught Spy
New member
Gun Tests magazine compared fluted and non-fluted barrels. They found that there was no significant reduction in heat between fluted and unfluted barrels, but that the fluted barrel did increase accuracy.
M16: You are right ... kind of ... The heating up part is all conductive heat transfer (one molecule heating up the next molecule) and unless we get into micro-thin flutes the heat-up rate driven by the weight of the barrel. The cooling, on the other hand, is mostly convective (metal heating up air) and its cooling rate is driven by surface area. So a design that increases the surface area for a given weight will stay cooler. I think that it depends on the design whether it would take longer for a heavier bull barrel to heat up than a lighter fluted barrel. In a situation where you are firing regularly for an extended time, the lighter fluted barrel should stabilize at a lower temperature because it is allowing more heat to escape into the air and given the same rate of fire we are putting the same amount of heat into the barrel.
I am surprised to hear that Gun Tests didn't find a difference in temperatures ... maybe they didn't fire it for an extended time ... this would probably be the only case where fluted would be better.
FWIW,
Saands
I am surprised to hear that Gun Tests didn't find a difference in temperatures ... maybe they didn't fire it for an extended time ... this would probably be the only case where fluted would be better.
FWIW,
Saands
You know the wind is a huge factor on barrel cooling. With no flutes, wind won't matter as much, but with flutes, it makes all the difference. Convection cools in the air, not conductance alone, and surface area is a great aid on that process when assisted by air currents.
When I made swords I put fuller grooves on each side of the blade on many of them, and this was done for several reasons. It made the edge of the blade wear differently, and changed the impact characteristics. From the design standpoint, it adds a great deal of strength too, because it forces stresses to specific areas which you can control by placing specific types of metals on those areas, or heat treating in a certain way to control the stress spread and the vibration. On a barrel these principals are the same, and the places where the barrel would blow open are certainly not the valleys of the flutes, but the thick areas between them. This spreads the stress differently and actually straightens the barrel as the inside is pressurized. It forces the stresses in a square shape instead of a linear circle, and it does a few other things as well. The principals are pretty simple but effective. I mean it's not miracle solution to accuracy, but I think it helps a great deal....
When I made swords I put fuller grooves on each side of the blade on many of them, and this was done for several reasons. It made the edge of the blade wear differently, and changed the impact characteristics. From the design standpoint, it adds a great deal of strength too, because it forces stresses to specific areas which you can control by placing specific types of metals on those areas, or heat treating in a certain way to control the stress spread and the vibration. On a barrel these principals are the same, and the places where the barrel would blow open are certainly not the valleys of the flutes, but the thick areas between them. This spreads the stress differently and actually straightens the barrel as the inside is pressurized. It forces the stresses in a square shape instead of a linear circle, and it does a few other things as well. The principals are pretty simple but effective. I mean it's not miracle solution to accuracy, but I think it helps a great deal....
Badger Arms
New member
For those of you who don't get it...
If you have two barrels of identical weight and length, the fluted barrel will be stiffer than the unfluted one. Take a steel rod and a sheet of metal. Bending the steel rod is easy, bending the sheet of metal width wise is next to impossible even if they were of the same weight. To make a fluted barrel, a BULL barrel is cut. The resulting barrel is lighter, but not as stiff as the starting barrel. A round barrel of the same weight will be less stiff and smaller in diameter.
Everybody is working on a computer right now. If you open up that computer and find the processor, you will find fluting and LOTS OF IT. Why? Because it cools better.
Sheez, this is so obvious I wonder why people have a hard time understanding the concept!
If you have two barrels of identical weight and length, the fluted barrel will be stiffer than the unfluted one. Take a steel rod and a sheet of metal. Bending the steel rod is easy, bending the sheet of metal width wise is next to impossible even if they were of the same weight. To make a fluted barrel, a BULL barrel is cut. The resulting barrel is lighter, but not as stiff as the starting barrel. A round barrel of the same weight will be less stiff and smaller in diameter.
Everybody is working on a computer right now. If you open up that computer and find the processor, you will find fluting and LOTS OF IT. Why? Because it cools better.
Sheez, this is so obvious I wonder why people have a hard time understanding the concept!
Art Eatman
Staff in Memoriam
The meaning of the benefits in stiffness and cooling:
If you're shooting 10-shot, rapid-fire strings in target competition, there may be some value in a fluted barrel.
If you ain't, there ain't.
, Art
If you're shooting 10-shot, rapid-fire strings in target competition, there may be some value in a fluted barrel.
If you ain't, there ain't.
, ArtI think most of the people here have been somewhat educated on the theory of fluted barrels. Yet, no one has any experience actually testing a barrel to see how long it takes to heat up and how long it takes to cool down. All this theoretical nonsense is crazy. What if the difference was so slight as to be meaningless? What if 30 minutes and 30 degrees difference meant the bullet did not change POI from a cold barrel shot? I'd guess that an extended session with similar Varmint rifles shooting the same number of rounds would not show a fluted barrel cooling significantly faster than an unfluted one.
Art Eatman
Staff in Memoriam
Aristophanes, it's been the best part of 40 years since I was "up" on vibrations, harmonics, springs, and all that. (I do know that Liberals give me bad vibes.)
For rifle barrels, what is important is that the vibrations are uniform from shot to shot. We know that if a barrel is not touching the forearm of the stock, there will be no change which is due to the barrel and stock heating--thus expanding--at different rates.
My uncle and Gale McMillan independently arrived at the conclusion that a shim between the barrel and forearm tip will improve accuracy. My uncle explained it to me as the shim acting like the shock absorber on a car, damping the vibrations to a uniform characteristic from shot to shot.
Gale commented that the shim would improve a not-quite-properly bedded rifle. There were two different standards working here; my uncle was working on "as-issued" rifles of the 1940s/1950s, and Gale was thinking more about his own style of target rifles.
Bottom line is that I put a shim in each of my rifles. Just enough thickness that it goes into place with about a five-pound pull separating the barrel and forearm tip. I make the shim with kitchen wax paper, folding a 3/4" strip back and forth until it's thick enough. The shim has always made an improvement, with the reduction in group size varying from rifle to rifle.
And that's all I know about rifle barrels and vibrations.
Art
(I do know that Liberals give me bad vibes.)For rifle barrels, what is important is that the vibrations are uniform from shot to shot. We know that if a barrel is not touching the forearm of the stock, there will be no change which is due to the barrel and stock heating--thus expanding--at different rates.
My uncle and Gale McMillan independently arrived at the conclusion that a shim between the barrel and forearm tip will improve accuracy. My uncle explained it to me as the shim acting like the shock absorber on a car, damping the vibrations to a uniform characteristic from shot to shot.
Gale commented that the shim would improve a not-quite-properly bedded rifle. There were two different standards working here; my uncle was working on "as-issued" rifles of the 1940s/1950s, and Gale was thinking more about his own style of target rifles.
Bottom line is that I put a shim in each of my rifles. Just enough thickness that it goes into place with about a five-pound pull separating the barrel and forearm tip. I make the shim with kitchen wax paper, folding a 3/4" strip back and forth until it's thick enough. The shim has always made an improvement, with the reduction in group size varying from rifle to rifle.
And that's all I know about rifle barrels and vibrations.
Art
Badger Arms
New member
Barrel and Bore temperature
With cooling, you have to look at both barrel and bore temperature. Steel heats up at a constant rate. In full-auto fire, the bore will heat up faster than ANY barrel will cool it. To this end, a fluted barrel is actually a poor choice as barrel mass is the most important factor. I'd go into this, but it'll take a much longer post and I'm not feeling spunky.
For 'rapid fire' where you take a little time to align your sights before you jerk the trigger again, fluted barrels take over. Let's talk about that a little. How do you measure the temperature of the barrel, in terms of actual energy absorbed or rate of dissipation? How do you measure barrel temperature? How did Gun Tests do it?
From practical experience, I shoot no more than two magazines through any rapid-fire rifle before I give it a chance to cool. Once it's cooled to where I can touch it without pulling my hand away immediately, I will fire again. Since I don't have two AR-15's with identical weight barrels, one fluted one unfluted, I am not in a position to judge anything. Besides that, my palms have never been calibrated for temperature sensativity.
For me, the bottom line is that I like a LIGHT rifle. A light rifle with many of the same benefits of a heavy rifle was worth the extra money I spent on fluting the barrel on my top-end. My DCM upper is not fluted because I don't need the gun to be lighter. In fact, I'm thinking of putting a buttstock weight in mine. Fluting would be absurd for me.
With cooling, you have to look at both barrel and bore temperature. Steel heats up at a constant rate. In full-auto fire, the bore will heat up faster than ANY barrel will cool it. To this end, a fluted barrel is actually a poor choice as barrel mass is the most important factor. I'd go into this, but it'll take a much longer post and I'm not feeling spunky.
For 'rapid fire' where you take a little time to align your sights before you jerk the trigger again, fluted barrels take over. Let's talk about that a little. How do you measure the temperature of the barrel, in terms of actual energy absorbed or rate of dissipation? How do you measure barrel temperature? How did Gun Tests do it?
From practical experience, I shoot no more than two magazines through any rapid-fire rifle before I give it a chance to cool. Once it's cooled to where I can touch it without pulling my hand away immediately, I will fire again. Since I don't have two AR-15's with identical weight barrels, one fluted one unfluted, I am not in a position to judge anything. Besides that, my palms have never been calibrated for temperature sensativity.
For me, the bottom line is that I like a LIGHT rifle. A light rifle with many of the same benefits of a heavy rifle was worth the extra money I spent on fluting the barrel on my top-end. My DCM upper is not fluted because I don't need the gun to be lighter. In fact, I'm thinking of putting a buttstock weight in mine. Fluting would be absurd for me.
Badger Arms
New member
Nimrod:
You are missing the point of fluting. It gives you more flexibility to tune the rifle to your needs. If weight were your major concern, EVERY ONE of your rifles would be fluted. For the weight, a Fluted barrel will be stiffer and inherintly more accurate. To say it's a sakes gimic ignores the half a pound to a pound of weight that it saves you and the increase in cooling it offers.
You say that it's an "Ever so slight" increase yet you don't attempt to back up your claim, only state your opinion. I can assert just as well that it's a significant increase in cooling, but don't have precision instruments and an endless supply of money to test my assertion, so it remains just an assertion. Why don't you think that fluting provides anything more than an 'ever so slight' increase in cooling?
Not a flame here, I'm just trying to understand why there is a school of thought out there on Fluting that holds this to be true yet doesn't back up their assertions. Do people just hear something and assume it's true? Where's the logic?
You are missing the point of fluting. It gives you more flexibility to tune the rifle to your needs. If weight were your major concern, EVERY ONE of your rifles would be fluted. For the weight, a Fluted barrel will be stiffer and inherintly more accurate. To say it's a sakes gimic ignores the half a pound to a pound of weight that it saves you and the increase in cooling it offers.
You say that it's an "Ever so slight" increase yet you don't attempt to back up your claim, only state your opinion. I can assert just as well that it's a significant increase in cooling, but don't have precision instruments and an endless supply of money to test my assertion, so it remains just an assertion. Why don't you think that fluting provides anything more than an 'ever so slight' increase in cooling?
Not a flame here, I'm just trying to understand why there is a school of thought out there on Fluting that holds this to be true yet doesn't back up their assertions. Do people just hear something and assume it's true? Where's the logic?