What can I say? I didn't name myself "greenhorn" for nothing. I have no idea what "fluting" is.

Fluting mills a barrel so it appears to have a number of U shaped channels running down the length of the outside of the barrel, reducing weight and creating a greater surface area for cooling. I have read one or two drawbacks to fluting, but can't remember them at this moment.


A picture at the bottom of this page explains it better than I can...

www.bushmaster.com/shopping/barrel-assemblies/

If you're referring to fluted bbls. this photo shows a fluted heavy bbl.



This is done to heavy barrels to lighten them & improve cooling. This decreases rigidity, compared to unfluted heavy barrels (The result of reducing cross-sectional area), by approx. 20-30%, but the increased cooling performance more than compensates for this. The big issue w/ fluting it is that stresses are introduced to the barrel during the groove cutting process. If done properly, the barrel's accuracy & grouping will remain pretty constant. It's also important that the grooves not be too deep, or else pressure threshold will be dangerously compromised. Seems that a fluted barrel should be cryonized to properly reduce those stresses.

Personally, I favor them (if done correctly) because they strike the best compromise between strength & light weight. They offer increased cooling performance over full heavies & are stronger than light bbls., being only about 50-60% heavier. They are a good idea in a M4-type, heavy bbl. carbine/CQB gun, but I wouldn't do it to a sniping rifle, where the added weight of a full heavy bbl. is actually beneficial. Overall, for the right type of gun, I think the benefits outweigh the deficits. Plus, they look bada$$ too . I will be swapping out the barrels of 2 of my own M4geries for these.

Revolver cylinders/wheels are also commonly fluted. The flutes are the grooves on outside of the cylinder. This is probably done to lighten the gun a little, & to enhance gripping the then cylinder when loading.

Fluting is also done on the INSIDE of a chamber (at least by H&K on their P7 9mm) as a way to reduce the contact area between the chamber wall and the outside of the spent shell. Then they vent a small amount of gas to further reduce the friction during the ejection of the shell. Stay safe

Don't forget the cylinders on revolvers -- done mostly to reduce weight.

Noah

Master_Blaster,

Fluting actually increases rigidity, not decreases it.

Not quite, a fluted barrel and a regular barrel of the same weight will have the fluted barrel stiffer, because the fluted barrel is larger in diameter.

www.riflebarrels.com/length.htm

Originally Posted By Troy: Originally Posted By djk: Fluting actually increases rigidity, not decreases it. Bzzzz. But thanks for playing. Departing guests will receive a copy of the home game... -Troy

Take a barrel that is fluted and one that is not but of the same weight as the fluted barrel and which one will be more rigid? The fluted one, of course.

One time, at band camp...

Originally Posted By Attman: One time, at band camp...

We have comedian on onboard. Anything else you have to say to the class?

Originally Posted By djk: Master_Blaster, Fluting actually increases rigidity, not decreases it.

Not trying to piss in anyone's puch-bowl, but torsional & lateral strength of an object such as a barrel is directly related to cross-sectional area. Fluting decreases this figure &, therefore, reduces the bbl.s strength/rigidity &, thus, its resistance to primary harmonics. Thus, if we have 2 bbls. of the same dimension, & we flute one of them, all other dimensions being the same, the fluted bbls. reduced cross-sectional area will result in decreased rigidity - it'll whip w/ greater amplitude than the non-fluted one.

Bushmaster used to claim that bbl. fluting increased rigidity, but later retracted it for this same misunderstanding.

Originally Posted By sparkyCG: Fluting is also done on the INSIDE of a chamber (at least by H&K on their P7 9mm) as a way to reduce the contact area between the chamber wall and the outside of the spent shell. Then they vent a small amount of gas to further reduce the friction during the ejection of the shell. Stay safe

Not just on the P7, but on the HK91 and 93 series as well. The extraction on the 91 is so violent, that without the fluting and the shell being "floated" by the gas, the brass would often be ripped in half.

Wasn't Fluting an NFL quarterback?

Nah! It's what Pan and Kokopelli do...

Originally Posted By marvl: Wasn't Fluting an NFL quarterback?

Doug, that is.