Picatinny Arsenal Developing Cobalt Alloy Barrels

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Engineers at Picatinny Arsenal, the military research and manufacturing facility, have been experimenting with machine gun barrels made from cobalt alloys.

Cobalt alloy barrels produced using the flow forming technique.

Army.mil reports

During testing, the first rifled, cobalt-alloy machine gun barrel ever produced using the “flow forming” process consistently reached high temperatures without degraded performance.

The proof-of-concept barrel was made of an alloy that contains more than 50 percent of the metal cobalt. Cobalt alloys are erosion- and corrosion-resistant metals that are designed to retain high strength during long-term exposure to high temperatures.

Cobalt alloys are frequently used in the aerospace industry, such as the hot-gas section of turbine engines, explained Leto. Cobalt alloys are also used as short liners for machine gun barrels.

“If you look at steel in a machine gun environment, it gets very hot at a high rate of fire,” said Leto. “The benefit of the cobalt alloy is that it is designed to operate in high-temperature, high-stress environments. It has the added benefits of corrosion and erosion resistance.”

[ Many thanks to Lance for emailing me the link. ]




Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


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  • ghardin

    The army used stelite lined barrels in 1919 Brownings during WWII and still uses a stelite chamber and throat insert in M2 .50 cal machineguns. It sure took them long enough to get to get from there to here.

  • http://gunsandbullets.wordpress.com Nate

    I wonder what the weight would be like compared to today’s steel barrels.

  • Lance

    This could help M-4 improvement program if they want a Carbine to dump mag after mag threw and not fail. Which is one of the requirements of the M-4 improvement program.

  • Rohan

    Nate,

    Heavier.

    The density of mild steel is approximately 7.85 g/cm3 (0.284 lb/in3)

    Cobalt is 9.89 g/cm3.

    The idea in to keep mechanical strength when hot, reducing or negating the need for spare barrels.

    The content of Cobalt in steel varies, but only 4-8% in high speed steel.

    50% Cobalt alloy with Ferris would be in 9g/cm3 ball-park.

    For a 20″ SAW barrel, thats 1.7kg up to 1.9kg, but no need for a spare.

  • Komrad

    according to Wikipedia, cobalt is can add heat resistance to alloys
    it’s also wear and corrosion resistant
    probably wont be much use to civies except as a replacement barrel for existing class 3’s
    might be a good thing to use in the IAR or M249 though

  • jdun1911

    You don’t stop shooting because the barrel is hot. You stop shooting because you think it might cause a cook off. This doesn’t solve the main problem. It does address barrel wear.

    Heat is the number cause of barrel destruction/damage. The question will be is it cost effective?

  • Some Guy

    Cobalt is pretty cheap, so I’d say so. It’s also supposedly easy to manipulate the stuff (it’s used in surgery join replacement), compared to stainless steel.

    However, my question is, how effective is it?

    A cobalt barrel would, theoretically reduce barrel wear but, by how much, and in what applications?

  • Lance

    @ Jdun1911

    Good point.

  • Arrkhal

    The main issue with cobalt alloys is that just about all of them are much weaker than high-speed steels at low temperatures, but much stronger at high temperatures. If you’re doing 99% of your shooting in single shot and short bursts, there’s no advantage at all, and the barrel might even wear out faster than a steel one (though if both are chrome lined, I’d guess there shouldn’t be as much difference). That’s why cobalt barrels never caught on, with anything that wasn’t tripod-mounted and crew-served. Like Rohan said, it’d make it so the M249 doesn’t need a spare barrel (as well as the M240 and M60), but that’s about it. The M4A1 “heavy” barrel already works fine for being able to dump all the ammunition that one guy can carry, as fast as he can reload and shoot.

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