Hex Fluted rifle barrels: the whys and wherefores


There have been a lot of questions about the honeycomb “Hex Fluted” barrels built by Legion Firearms. A lot of people wonder if that’s strictly an aesthetic feature or even a gimmick, others challenge the idea that such construction actually strengthens or improves the barrel. I talked to Jamie Wehmeyer and Chris Reeves from Legion at length about these issues to try to illuminate things.

Note: in the interest of full disclosure, I will tell you up front I’ve had the opportunity to shoot a T&E model LF15D extensively and I was very impressed. It was certainly more accurate than I could exploit at my skill level and was over 7k rounds without cleaning when I had it. I do not own one.

Legion rifle barrels were R&Ded for 3 years before they went into production. They are not CHF (Cold Hammer Forged), they’re a 416R ordnance grade stainless steel. They’re chambered in 5.56mm NATO, cryogenic treated, 3-groove polygonal stress-relieved. Every  barrel is Cerakoted to prevent any rusting or external oxidation. There are a total of nearly 30 procedures and treatments that go into the barrels, though they understandably don’t go into detail about them. One obvious physical feature is Hex Fluting.

Essentially, the Hex Fluting design is based on the study of vibration—how it works, when it stops.

Wehmeyer clarifies, “I’m talking about the dissipation of an instance of vibratory motion. Call it motion, tremor, an oscillation, whatever term you prefer. It’s the underlying physics of it that are significant to the Hex Fluted barrel.”

Vibrations travel for longer distance through a curve than they will through a straight line or an angle. The so-called ‘honeycomb’ barrel capitalizes upon that.  Consider the difference between striking a steel drum vs. a steel box: a steel drum will continue to vibrate for as long as the shape can hold it, whereas a steel box will hold the vibration only to the closest corner.

Wehmeyer says, “The long term study of vibrations has yielded facts that the firearms industry has failed to acknowledge and capitalize upon for years. It’s not that the industry is dumb or naïve, it’s just that the different sciences frequently fail to cross-communicate enough to really affect each other in any productive manner.”

Legion guarantees their rifles will shoot sub MOA with cheap XM193 or PMC55 type ammunition. They’ve achieved one-hole groups with 3 rounds of 77 grain OTM (Mk262 Mod 1) 5.56mm at 100 yards, and every proficient shooter I’ve personally talked to has verified just how accurate they really are.

Another advantage to the Hex Fluted barrel is heat dissipation.

“Simple science fact,” Jamie says. “A greater surface area is going to yield greater heat dissipation given no disparity in material and relative mass. Also, strength and rigidity should not be measured by how much material an object contains but rather by its ability to retain its original form. [emphasis added] Our barrels are built the way they are for strength, heat dissipation and accuracy. The aesthetics of it are purely a byproduct.”

If you have any further questions, please advise and I will try to get an answer or will ask the Legion guys to watch the comment section so they can address them directly. Legion is also available on Facebook.


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