what can fluting my rifle do for me

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ny_vin18

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i have a bushmaster m4a2 with a 16'' barrel, say i wanted to flut my rifle, what will this do for me when i go and fire my bushmaster m4 at the range. oh one more ? i use federal .223 fmj is their any other even better ammunition brands i can try in .223 thanks guys.


sencerely

vinnie.
 
It can lighten your wallet.
A friend that has a milling machine fluted his 16 in AR barrel and has no problems hitting man sized targets at 300 yds. I was amazed how much he was able to take off. I think he used a 1/8 or smaller bit that ended in a point.

The same guy showed me how to flute my wifes Savage 112 with 223, 221/300 and 308 barrels with no change in impact after 50 rnds. We never tried to shoot a lot of rounds fast through it though.
 
in theory...

It creates greater surface area and thus will allow your barrel to cool faster, making POI shift LESS not more. If done improperly, I could see it having adverse effects. I just think that it mainly looks cool, and that its “coolness factor” often outweighs any real benefit. That said, I like fluted barrels, and if they are offered, I will usually opt for one so long as I don’t think that they ruin the over-all look of the gun.
 
and that its “coolness factor” often outweighs any real benefit
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Speaking of weight I would say one very real benefit would be just that: saving weight. I don't know about other rifles but 10/22 fluted bull barrels are noticeably lighter than non-fluted barrels. I would imagine it's even more noticeable on .308's and such. Makes a big difference when lugging the rifle around!
 
Fluting your barrel:
1. Lightens up the weight of the barrel.
2. Increases surface area for supposed better cooling.
3. Supposedly makes the barrel more stiff. I've never seen actual data on this, just claims.
4. Depending on your eye, there is always the 'coolness' factor.
 
Fluting a barrel does not make it stiffer. People often are confused about this.

What is true is that a fluted barrel is stiffer than a non-fluted barrel of the same weight and length. That is because a fluted barrel of the same weight will have a larger diameter.

As far as cooling, a fluted barrel will have more surface area, and thus cool faster. However, a fluted barrel of the same diameter as a non-fluted one has less mass and therefore it will heat faster too.

The only real advantage of a fluted barrel is that for the same weight as a non-fluted one, it will be stiffer.
 
Question - Can a rifle barrel be fluted post manufacturing?
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BSR,

Yes, but don't do it. Only flute a barrel as part of the barrel manufacturing process, and then, only if it is a cut rifled barrel like Krieger, Obermeyer, Rock, etc.

Don
 
As far as cooling, a fluted barrel will have more surface area, and thus cool faster. However, a fluted barrel of the same diameter as a non-fluted one has less mass and therefore it will heat faster too
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Great post. The idea that a fluted barrel will "cool faster" is something parroted by shill gunwriters who don't know enough, and aren’t being paid, to challenge questionable technical claims . The basic problem is the rate of heat transfer to air. At some point, a very small point, you cannot overcome the "thermal conductance" of the material. http://en.wikipedia.org/wiki/Thermal_conductivity. In practice, unless there is a forced air flow over the fluting, there is at best a minimal improvement in heat transfer.

What is done for weapons that shoot a lot of ammunition fast, is that those barrels are made heavier. That way you can fire more rounds before the barrel finally gets too hot.

I don't have a fluted barrel. Removing material makes the barrel less stiff. Barrels have a lot of internal stresses. Removing material will just increase the probability that it will walk as it heats up.
 
I have two custom built rifles with fluted barrels. One has a Krieger barrel with a MTU contour (.930" at 26") in .30-06, and the other is an Obermeyer with an AMU contour (.900" at 28") in 6.5x55. Both are used in 1,000 yard competition, and both will heat up when 25-30 rounds are fired in 30 minutes, so don't get a rifle barrel fluted simply to dissipate heat. IMHO, the only reason to get a barrel fluted is to end up with a slightly stiffer barrel when using a heavy contour barrel and to balance the rifle.

Don
 
Nothing is better for competition/accurate shooting than a solid stainless bull barrel. Everyone that shoots seriously for national/international matches uses only one type. Fluting and all that hype is expensive and not really beneficial. It does shave weight from the weapon and in some RARE cases this is important to some individuals for personal reasons only (3-position comes to mind and so does hunting if they really wanted to use a supreme accurate firearm and carry it around) but thats about it. Hope this helps. :D
 
Fluting and all that hype is expensive and not really beneficial.
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Alphazulu6,

Hmmm, fluting costs about $100. What is $100 when you spend about $2500 on a rifle? You see more than a few fluted barrels in F Class competition. I'm curious as to what LR competition you shoot?

Don
 
Given the OP's setup, the only reason to flute the barrel is to change the balance of the weapon. Do you want it to be less nose-heavy? If so, fluting is an option. The drawbacks are:

1. $$$$$$$
2. Decreased stiffness, though not as much as would be experienced by turning the barrel down to achieve the same weight.
3. Faster heating and cooling (mostly due to reduced mass, not any effect of surface area).

Mike
 
Fluting won't offer any measurable difference to cooling until your barrel reaches temps that are already causing damage. If not done correctly, it will affect your accuracy. Your also altering the natural grain structure of the barrel, giving it the potential to react inconsistently.
 
If not done correctly, it will affect your accuracy. Your also altering the natural grain structure of the barrel, giving it the potential to react inconsistently.
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True. This is why it is only recommended on cut rifled barrels. The button rifling and cut rifling process is done in two distinctly different ways. With button rifling, the contouring and fluting (if it is to be done) must be done AFTER the barrel is reamed and rifled. This process of removing metal from the exterior of the barrel induces stresses which must be removed by stress relieving the barrel. Removing metal from the exterior also effects the interior bore dimensions. With cut rifling, on the other hand, the contouring and fluting (if it is to be done) is done BEFORE the bore is reamed and rifled, so there is no stress or grain structure change, or change in the bore dimensions. As Boots Obermeyer said, "Any fool can pull a button through a barrel!".

Don
 
I don't see how fluteing can significantly aid in cooling. the flutes run in the wrong direction to contribute to good air flow, in fact a flute dead bottom would tend to hold air in place, assuming absolutely no movement of the gun. If you want maximum cooling, get a very large diameter then have fins cut radially along probably about 1/3 the length, chamber end. Look at pictures of some of the old Thompson sub machine guns .
 
Great post. The idea that a fluted barrel will "cool faster" is something parroted by shill gunwriters who don't know enough, and aren’t being paid, to challenge questionable technical claims . The basic problem is the rate of heat transfer to air. At some point, a very small point, you cannot overcome the "thermal conductance" of the material. http://en.wikipedia.org/wiki/Thermal_conductivity. In practice, unless there is a forced air flow over the fluting, there is at best a minimal improvement in heat transfer.
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Radiative cooling is probably more important than convection cooling, for something that's a couple hundred degrees. I could see how fluting could theoretically double the radiative cooling rate, since it is a linear function of the surface area.

However, as others have pointed out, what you gain in cooling, you lose in thermal mass, so your peak temps will be as high or higher with a fluted barrel than a solid barrel of the same profile, so IMHO weight is really the only reason to go with a fluted barrel over a solid.
 
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