US Army Armaments Center Patents New M4 Heavy Barrel

Will P
by Will P
The US Army’s new heavy barrel concept for the M4.

“The M4A1 Carbine is a lightweight, 5.56 millimeter, magazine fed, gas operated, air cooled, shoulder fired weapon.” For many years, US Army Infantrymen have had this phrase, or a slight variation of it, drilled into their heads until they could recite it perfectly. The above version was the one I learned verbatim during my time training at Sand Hill on Fort Benning, and then serving as an 11C with the 10th Mountain Division at Fort Drum.

Those of us grunts who shared a particular interest in firearms would often find ourselves discussing our various weapons, including the M4s that were our constant companions. We consulted about the modification our regular M4s had undergone to become M4A1s, our ACOGs vs the M68 Close Combat Optic, and what else we would like to see changed. One recommendation that came up from time to time was the idea of changing to an HBAR, or Heavy Barrel, and how that might improve effectiveness. It appears that the US Army’s CCDC (Combat Capabilities Development Command) Armaments Center may agree, as they have recently patented a new heavy barrel upgrade design.

A July 9th press release states:

A soldier employing an M4 in a typical modern configuration, equipped with an ACOG optic and PEQ-15 infrared laser.
Army invents new heavy barrel for M4 – TechLink

Two small arms engineers at the U.S. Army’s CCDC Armaments Center have invented a new M4A1 barrel for extended cyclical fires.

On Tuesday, the Army was granted a 15-year design patent, which is now available for license to businesses that would manufacture the barrel.

Thomas Grego and Adam Foltz designed the heavy barrel at the Picatinny Arsenal in New Jersey. It features spiral fluting in three distinct areas that increase the exterior surface area of the barrel as well as reduce overall weight.

The new barrel dramatically reduces the risk of barrel failure or premature ammunition detonation, i.e., a cook-off, by diffusing heat faster than the conventional M4A1 heavy barrel, which soldiers had reported were failing during combat in Afghanistan.

“(The M4A1) allows us to fire a better suppressing fire,” Lt. Col. Terry Russell told the Army Times in 2015. “At some point, a barrel is going to bend. It could be solid steel, but as soon as you reach a certain heat point it’s going to do some damage to the barrel. … But (the improved barrel) would have helped out to a certain degree.”

The new barrel’s fluting has fin spacing and a thickness that is optimized for heat dissipation and weight; the fin height gradually tapers down.

The design patent is the second patent the Army has received for the new barrel. In April, a 20-year utility patent was also granted.

Brian Metzger, a senior technology manager at TechLink, is facilitating licensing discussions for companies interested in producing the barrel.

“The design patent reinforces the utility patent, makes it a complete package for a licensee,” Metzger said Wednesday morning.

From the US Army's M4 manual, this shows the current barrel in a standard upper receiver setup.

From the US Army’s M4 manual, this shows the current barrel in a standard upper receiver setup.Whether this change actually gets put into practice remains to be seen, but it’s at least interesting as a concept. What do you think? Would this barrel swap away from the current 14.5″ version be a good idea or not? Please let us know in the comments what your take is. See you at the range!

Photos courtesy of the US Army.
Will P
Will P

Lifelong hobby/sport shooter and hunter, former US Army infantryman, perpetual firearms student. Always seeking to become better and learn more. Interested in a wide variety of shooting disciplines, and passionate about all kinds of guns. Contact on Instagram: @WillTFB

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2 of 144 comments
  • A.J.  Hodges A.J. Hodges on Jul 14, 2020

    Fluting for heat dissipation is common in other industries but in firearms it's usually for weight savings and aesthetics. I am interested to see the results of testing whether the idea makes a difference in practical application.

  • Mike Mike on Jul 25, 2020

    Not an invention, they just stole the cooling ring idea from Steyr.