US Army Invents New Heavy Barrel for M4

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Army invents new heavy barrel for M4

By TROY CARTER

TechLink Staff Writer

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.
 
Army: we’re patenting this ground breaking new barrel design
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Green Mountain Barrels: umm, we already did that

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Army: oh no, you see... our fins are twisted
 
The phrase "BOHICA" comes to mind...

Oh, and I wonder what that does to barrel harmonics?
 
And they have 3 sections of fins not 2

yeah, the GMB one I posted was an 11.5” rather than a 14.5”. That bare grenade launcher mount section on the 14.5” would be at the threads of the 11.5”. But I’m sure the Army would use that as being novel and non-obvious to get a patent. ;)
 
The phrase "BOHICA" comes to mind...

Oh, and I wonder what that does to barrel harmonics?

It’s fine for harmonics. Just a different form of fluting to reduce weight while maintaining rigidity and increasing cooling. Just funny that they were able to patent it.
 
It’s fine for harmonics. Just a different form of fluting to reduce weight while maintaining rigidity and increasing cooling. Just funny that they were able to patent it.
It’ll need a barrel tuner but the reverse spiral pattern negates the effect of spindrift so overall it’s a win.
The twisted fluting lets them thread on a pair of nuts that they can lock together as a tuner, obviously.

The only reason Green Mountain didn't get their own patent? Fins have been done befo
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I'm no engineer, but wouldn't spiral cut heat sink fins largely defeat the purpose of having a heavy barrel--rigidity? I would have thought linear fins would have been more structurally appropriate if you had to cut fins into a heavy barrel for better heat disbursement. Maybe the spiral cuts result in a lot more surface area.
 
Well, at least we can hope that this new barrel design would cost less than those uniforms that only worked in no environment. [rofl2]
Let's just hope Natick Labs wasn't in charge of this billion dollar project.
 
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That's kind of what I was thinking would make more sense, but built right into the barrel profile. Here, I'd imagine you'd need a lot of thermal paste for efficient heat transfer to allow for the heat sink to work optimally, just like a CPU and fan.
What you're describing is standard fluting. How fine you're willing to get them will set your ratio of volume to surface area. Of course, Al is better at this than steel. Your intuition that the twisted flute increases surface area is correct. While straight fins may be stiffer than the twisted ones in any given plane, the twisted flutes are stiffer than a plain pencil barrel. Since everything is a compromise, the designers probably decided that this is stiff enough for their needs, while balancing increases in weight and cooling efficiency.

And it looks cool. Which means they'll sell a million extra barrels to LARPers that just have to have the same gear the big boys are running. Now we need to figure out how to get the quoting process to account for this sort of speculation - thus driving down the demand on our tax dollars, and freeing us up to buy more super sweet gear for ourselves.
 
What you're describing is standard fluting. How fine you're willing to get them will set your ratio of volume to surface area. Of course, Al is better at this than steel. Your intuition that the twisted flute increases surface area is correct. While straight fins may be stiffer than the twisted ones in any given plane, the twisted flutes are stiffer than a plain pencil barrel. Since everything is a compromise, the designers probably decided that this is stiff enough for their needs, while balancing increases in weight and cooling efficiency.

And it looks cool. Which means they'll sell a million extra barrels to LARPers that just have to have the same gear the big boys are running. Now we need to figure out how to get the quoting process to account for this sort of speculation - thus driving down the demand on our tax dollars, and freeing us up to buy more super sweet gear for ourselves.

But from what I've seen, traditional fluting cuts appear to be more for weight consideration as oppose to maximum surface area. I was thinking tighter cuts to create more of a fin, like the JP heat dissipator that Rob posted.
 
Trying to make a rifle do what a belt fed machine gun does.
There is a reason a belt fed machine gun has the ability to quickly change barrels...
 
Waste of time and money. Not needed.

Do you know how often barrels are changed? It’s not like they’re going to remove good barrels and put on these. They’ll just replace as they need to, if this barrel is fielded.

As for whether it’s needed or not, I think it’d be worthwhile to allow an M4A1 to provide suppressive fire occasionally and more reliably. The SAW/Mk46/Mk48 can’t be everywhere.
 
But from what I've seen, traditional fluting cuts appear to be more for weight consideration as oppose to maximum surface area. I was thinking tighter cuts to create more of a fin, like the JP heat dissipator that Rob posted.
You're correct.

Fluting is a balance of weight and stiffness. It has the added benefit of increasing surface area to volume ratio. This improves thermal effects. Thinner ribs would be more efficient at this, but would also be less sturdy against side loading (BH³ and all that) risking damage. They'd also be harder to manufacture. This profile is, in effect, a multi-start thread.

The heat sinks that Rob posted are almost certainly extruded. This makes them relatively inexpensive to produce. And, because they're aluminum, they will have way better thermal characteristics than anything you'll ever get out of steel. It's also way less rugged - but it's a device for gamers, so they don't really have to worry about getting FOD in there and damaging the barrel.
 
As for whether it’s needed or not, I think it’d be worthwhile to allow an M4A1 to provide suppressive fire occasionally and more reliably. The SAW/Mk46/Mk48 can’t be everywhere.
It sounds like this is inspired by, if not a direct result of the project that gave us the M27 IAR. Especially now that the Marines are talking about giving M27s to every infantryman, anything to improve rifle reliability in an expanded role seems worthwhile.
 
It sounds like this is inspired by, if not a direct result of the project that gave us the M27 IAR. Especially now that the Marines are talking about giving M27s to every infantryman, anything to improve rifle reliability in an expanded role seems worthwhile.

My thoughts too.
 
Do you know how often barrels are changed? It’s not like they’re going to remove good barrels and put on these. They’ll just replace as they need to, if this barrel is fielded.

As for whether it’s needed or not, I think it’d be worthwhile to allow an M4A1 to provide suppressive fire occasionally and more reliably. The SAW/Mk46/Mk48 can’t be everywhere.

As I recall there was one SAW per fire team, two per squad in an Army Infantry Squad. Add in one M203 per fire team, two per squad and and infantry squad has enough fire power to be the base of fire for another squad. Add in a weapons team attachment with M240's to a platoon and there is plenty of firepower to maintain fire superiority at the platoon level. Not saying the Army shouldn't look to improve the capabilities of M4's, but from a tactical standpoint, seems like it's not needed, especially considering much of this is coming from operations in Afghanistan where vehicles were used extensively and vehicle mounted M2's and M240's were available.

It kind of reminds me of the shift to DMR's. Every squad should likely have at least one Designated Marksman with a >=7.62mm rifle. The Army shortens the barrels of M16's and you get the M4, then they cry that the balistics of 5.56 out to 800-1000 yards is problematic in environments like Afghanistan where distances are greater and elevation is an issue. The solution isn't to replace M4's with some other rifle, it's to add a DMR to fire teams and squads.
 
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As I recall there was one SAW per fire team, two per squad in an Army Infantry Squad. Add in one M203 per fire team, two per squad and and infantry squad has enough fire power to be the base of fire for another squad. Add in a weapons team attachment with M240's to a platoon and there is plenty of firepower to maintain fire superiority at the platoon level. Not saying the Army shouldn't look to improve the capabilities of M4's, but from a tactical standpoint, seems like it's not needed, especially considering much of this is coming from operations in Afghanistan where vehicles were used extensively and vehicle mounted M2's and M240's were available.

...

You’re correct about the machine gun numbers. But in Afghanistan there has been extensive dismounted operations in the mountains. Hell, even in Iraq we had a lot of dismounted operations infilling to an objective or while conducting patrols through palm groves. If you’re in a squad element and need to conduct a squad attack, you only have one SAW/Mk46/Mk48 to provide suppressive fire while the other fire team moves in.
 
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The phrase "BOHICA" comes to mind...
T
Oh, and I wonder what that does to barrel harmonics?
They are trying to mitigate the damage caused by M855A1 rounds and their absurdly high pressures, causing gas port erosion in the barrels. Even if they solve the barrel problem, they still have the issue of premature bolt/carrier failure. Instead of spending boatloads of taxpayer $$$ hot-rodding the 5.56mm round, just move on to a larger caliber.
 
Maybe it's time for a 7.62x39-based AR for .MIL...? [devil2][pot][devil2]
 
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They are trying to mitigate the damage caused by M855A1 rounds and their absurdly high pressures, causing gas port erosion in the barrels. Even if they solve the barrel problem, they still have the issue of premature bolt/carrier failure. Instead of spending boatloads of taxpayer $$$ hot-rodding the 5.56mm round, just move on to a larger caliber.

That’s not what this barrel is for at all. This is to reduce rapid wear on the barrel or premature destruction of the barrel during high rates of fire. It has nothing to do with the M855A1.

The M855A1 isn’t supposed to hot rod the 5.56 in the sense of making it perform like a larger cartridge. It increases the range of reliable fragmentation due to bullet design, and is more precise than M855. It’s designed for 14.5” barrels rather than 20”, but isn’t supposed to really extend the overall effective range past that of an M16A4. Just optimizations. And the wear on parts from M855A1 only marginally shortens maintenance cycles. And new magazines have also eliminated the minor issue of pitting on the feed ramps.
 
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US Patent Application for Flowforming Gun Barrels and Similar Tubular Devices Patent Application (Application #20100236122 issued September 23, 2010) - Justia Patents Search

I worked for these guys in MA, we had M4 barrels that could withstand 1000+ rounds with no issues, breach of the gun would catch fire before barrel would overheat. This was 10 years ago, my boss always said the lives we could have saved could not be counted if only we had won the political BS game in getting the contract.
 
US Patent Application for Flowforming Gun Barrels and Similar Tubular Devices Patent Application (Application #20100236122 issued September 23, 2010) - Justia Patents Search

I worked for these guys in MA, we had M4 barrels that could withstand 1000+ rounds with no issues, breach of the gun would catch fire before barrel would overheat. This was 10 years ago, my boss always said the lives we could have saved could not be counted if only we had won the political BS game in getting the contract.
Not only did I just get to read an awesome patent, I learned about a new-to-me MFG technology. Thanks!
 
Do you know how often barrels are changed? It’s not like they’re going to remove good barrels and put on these. They’ll just replace as they need to, if this barrel is fielded.

As for whether it’s needed or not, I think it’d be worthwhile to allow an M4A1 to provide suppressive fire occasionally and more reliably. The SAW/Mk46/Mk48 can’t be everywhere.

First thing that came to mind when I saw this, our boys will have to change saw etc barrels less often. Having couple of extra ones on a kit it will increase the firing time. Last thing anyone wants is to change barrels mid fight.
 
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