Fluting Barrels; Interesting Stuff

[Bart B.]

Found this thread from another one:

http://www.thefiringline.com/forums/showthread.php?t=340042&highlight=fluting

Really liked Longrifle's comment about why people flute barrels:

This whole subject is 7th grade science. Barrels are fluted because they look cool to some people and its a way to charge more for a gun. There's your real reason.

I've always though it was 8th grade science. Guess I was wrong.

 

[Maverick223]

The flutes impart a greater moment of inertia and thereby offer a better strength to weight ratio (not necessarily stronger, but always stronger than a barrel of the same material and weight) and also provide superior cooling with respect to cylindrical barrels. I will concede that the primary reason for flutes is for aesthetics.

 

[WardenWolf]

Fluting lightens a barrel while maintaining or improving strength, is what it boils down to. Any multi-angled surface is always going to be more rigid than a simple surface. It's the same reason sword blades have a groove in them. It's not a "blood groove" or any of the countless incorrect things people call it. Its purpose is to lighten the blade while increasing rigidity.

 

[Bart B.]

Mike the Wolf claims:

Fluting lightens a barrel while maintaining or improving strength, is what it boils down to. Any multi-angled surface is always going to be more rigid than a simple surface.

Well, mechanical engineers will disagree. Any time you remove metal from the surface from a barrel, you remove material that makes it stiff and strong.

What's stronger and stiffer to do anything on:

A wood floor made with 2 x 6's stood on edge glued to each other?

A wood floor made with alternating 2 x 4's and 2 x 6's stood on edge glued together?

Check out the following from an ME.....

http://www.snipercountry.com/Articles/RealBenefitsBarrelFluting.asp

 

[JohnBT]

Fluting after rifling can cause problems with the bore distorting.

To save me a bunch of typing:

www.ar15barrels.com/faq.shtml

"I now only want to make barrels from a Krieger fluted barrel blank. They are one of the only companies doing it the "right" way. The right way to do fluting is after boring and profiling, but before rifling and final lapping. "

 

[Bart B.]

JohnBT says a good one:

Fluting after rifling can cause problems with the bore distorting.

And right you are.

Fluting a button rifled barrel makes the bore under the flutes to be a tad larger.

On a hammer forged barrel, it makes the bore tighter.

Cut rifled barrels have the least bore dimensions change after fluting.

All of 'em will have a bump in dimensions at the ends of the fluted area.

Best of all methods are cut rifled barrels where fluting's done after boring and profiling but before rifling and final lapping to dimensions.