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  1. #41
    Senior Member M1917 Enfield's Avatar
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    Quote Originally Posted by RobertMcC View Post
    I lugged the C6 for many years. I loved it. My unit was known for machine guns and mortars. Too bad Mortar platoon was disbanded shortly after I joined.



    I wouldn't really call the BREN or C2 LMG's, but more SAW.


    From what I read, brass case, does act as a heat sink, to carry away from some of heat. I wonder if Poly case will distort when really hammering on a machine gun, to the point of cook offs?
    From post #12 -

    "The U.S. Army and any AR shooter can mitigate the parts failure that comes with such high pressures by reducing heat in the chamber. Enter True Velocity's approach to the polymer case. Parts that don't get hot last much longer than parts that do.

    A polymer case is an insulator rather than a conductor. When the cartridge fires, the case contains the heat and pressure and directs it all down the barrel. Instead of super-heating brass that then heats the chamber around it, the only heat the entire barrel sees is what's found in the bore. Heat will certainly move from the barrel around the bore back into the chamber area, but keeping the heat out initially will reduce how quickly the AR bolt heats up, thereby prolonging its life. The way this ammunition manages heat should appeal to military and high-volume shooters alike.

    With the ammunition doing well in both the accuracy and chronograph departments, I shifted my focus to see if I could get a gun to choke. My first choice was FN's Mk 48 belt-fed machine gun chambered in 7.62 NATO.

    The Mk 48 has a cyclic rate of 700 rounds per minute. It was the most cartridge-abusive platform available to me at our test range. Since the bolt speed is so fast, cartridges get jerked around and shoved aggressively into the chamber. The Mk 48 gobbled up an entire 50-round belt without issue or pause.

    True Velocity is also working closely with Dillon Aero. They used Dillon's M134 Minigun to fire thousands of rounds for several months. The M134 is also chambered in 7.62 NATO and fires 3,000 rounds per minute. The standard loadout on a vehicle equipped with an M134 is 9,000 rounds, so the True Velocity ammunition yields a 240-pound weight savings per basic load. The M134 reliably cycled the ammunition, a claim that no other polymer-cased ammunition can make.

    A worrisome trait about the M134 is the way it can cook-*off live rounds with brass-cased ammunition. A cook-off occurs when a cartridge sits in a hot chamber and spontaneously fires because the powder inside the case becomes hot enough to ignite. Dillon has a 1,500-round test they run on the Minigun and brass-cased ammunition will cook-*off after sitting in the chamber anywhere from 3 to 60 seconds. Dillon recorded a 20-percent lower bore temperature using True Velocity ammunition (thanks to the case insulating the chamber), so they ran a 2,200-round test on the ammunition. Dillon had to wait 5 minutes before one case got hot enough to melt — but the bullet never left the barrel. The absence of cook-offs in a Minigun should bring a welcome sigh of relief from special operations soldiers and aviators alike.

    United States' Special Operations Command (SOCOM) has been aggressively monitoring the individual health hazards associated with shooting thousands of rounds per year. SOCOM first became aware of the problem when soldiers working and training in shoot houses tested positive for dangerously high lead levels. SOCOM's testing showed that 30 percent of the toxins any shooter is exposed to came from the gases emanating from freshly fired brass. Arsenic, cyanide and a bunch of nasty stuff is used to make copper and brass products. Super-heating brass in a chamber causes those elements to burn out of the brass for up to an hour after the cartridge fires. Those gasses accumulate in shoot houses and indoor ranges where patrons gain exposure. True Velocity indicated that none of this is a problem with their ammunition.

    To sum up this exclusive process, True Velocity's ammunition is light, accurate, consistent and robust. It can survive use in everything from belt-fed machine guns to Miniguns. While the ammunition will likely be fielded by the military before it hits the commercial market, I predict that soldiers and civilians alike will enjoy the benefits of reliable polymer-cased ammunition in the very near future."
    I live among lots of sheeple and dim witted who like to think they are good Canadians for voting Lieberal

  2. #42
    Senior Member M1917 Enfield's Avatar
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    Quote Originally Posted by kennymo View Post
    It’s called 270 Winchester
    Except in a lot shorter polymer case, weighs a lot less for a battle load, still penetrates level 4 armour out to 600 metres and still gets decent performance fired from barrels under 18"
    I live among lots of sheeple and dim witted who like to think they are good Canadians for voting Lieberal

  3. #43
    Senior Member M1917 Enfield's Avatar
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    Quote Originally Posted by Grimlock View Post
    Looking at the pictures, it's got no neck. There are a couple mentions of "telescoped", which probably means the bullet sits way back in the powder. It would probably not work with a brass case in that configuration. It would take years for other ammo companies to make something that fits, and 20 years for the patents to come off, so I don't know how we'd ever see this in use for people who have to buy their own ammo.
    This new Polymer ammo probably does not need a neck like brass ammo does to hold and retain the projectile and not having a neck probably allows more powder space too for optimum performance.

    I'm just guessing here but probably the last thought the military designers of this new ammo are considering is future use and availability to civilian sports shooters.
    I live among lots of sheeple and dim witted who like to think they are good Canadians for voting Lieberal

  4. #44
    Senior Member Grimlock's Avatar
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    Quote Originally Posted by M1917 Enfield View Post
    This new Polymer ammo probably does not need a neck like brass ammo does to hold and retain the projectile and not having a neck probably allows more powder space too for optimum performance.

    I'm just guessing here but probably the last thought the military designers of this new ammo are considering is future use and availability to civilian sports shooters.
    They should be more considerate.

    They make money off of used brass, although the cost savings of this probably offsets it, and I'm sure it's tiny in the grand scheme of things. The designers aren't the military, they're GD, and you can bet they're already trying to find a way to sell the stuff to us. You can definitely bet that SIG has a plan to sell us that rifle. They're not Colt: they know the civilian market is important. I'm wondering if there will be a close-enough chambering (ie whatever the brass stuff in the pictures is).

  5. #45
    Senior Member M1917 Enfield's Avatar
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    Quote Originally Posted by Grimlock View Post
    They should be more considerate.

    They make money off of used brass, although the cost savings of this probably offsets it, and I'm sure it's tiny in the grand scheme of things. The designers aren't the military, they're GD, and you can bet they're already trying to find a way to sell the stuff to us. You can definitely bet that SIG has a plan to sell us that rifle. They're not Colt: they know the civilian market is important. I'm wondering if there will be a close-enough chambering (ie whatever the brass stuff in the pictures is).
    Actually the 6.8mm projectile has already been designed and tested by the US military and was presumably tested in a similar sized brass prototype case to meet their case size/length, velocity and penetrating requirements, they are now merely asking for tenders from industry to develop a lighter polymer cased that they can then mass produce at Lake city.

    The successful eventual ammo designer will make way more money from licencing and royalty's from the adopted manufacturing method chosen by the military and then other countries than they will ever get from sporting shooters from a cartridge not even in commercial manufacture or with any civilian chambered firearms that are available anytime soon.

    Read post #28 for more details.

    Here is another two examples of another round from another maker that was tested but did not win out in their tender.

    PCP-Ammo-Polymer-Cased-Lightweight-Machine-Gun-Ammo.jpg


    BTW, TrueVelocity (a small Texas based startup company) teamed up with the huge sized General Dynamics are they were able to show that their technology was viable and it benefits GD to have them onboard as a partner.
    Last edited by M1917 Enfield; 09-12-2019 at 07:13 PM.
    I live among lots of sheeple and dim witted who like to think they are good Canadians for voting Lieberal

  6. #46
    Senior Member Grimlock's Avatar
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    The initial order is for 250,000 rifles. There are 20 million AR15s in civilian hands in the US. People will want it, and they will get it, and the money they get from civilian sales will be significant. The US DOD demands to see your books these days and tells you what profit you're going to get on a job. The days of $300 toilet seats are over. This new Lake City line will be built to handle war demand. For peacetime they're going to want to keep it running and sell some.

  7. #47
    Senior Member M1917 Enfield's Avatar
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    Quote Originally Posted by Grimlock View Post
    The initial order is for 250,000 rifles. There are 20 million AR15s in civilian hands in the US. People will want it, and they will get it, and the money they get from civilian sales will be significant. The US DOD demands to see your books these days and tells you what profit you're going to get on a job. The days of $300 toilet seats are over. This new Lake City line will be built to handle war demand. For peacetime they're going to want to keep it running and sell some.
    Yeah, initially all production of these guns and ammo will be for the military only but hopefully I'm sure some later production will bled into the civilian sporting market unless the progressive socialist minded Liberals of the USA and Canada get their way like in those in New Zealand and ban all military type rifles like they are always harping on with their want of AR-15/M16 type "assault" rifles eventually banned from civilian ownership.
    I live among lots of sheeple and dim witted who like to think they are good Canadians for voting Lieberal

  8. #48
    Senior Member Mark-II's Avatar
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    Quote Originally Posted by Rory McCanuck View Post
    I think the idea is that the plastic case is such a good insulator that none of the heat actually gets transferred to the chamber.
    Now, does that mean the heat goes out the ejection port or all of it gets sentdown the barrel?
    I read the bit about insulating the powder from barrel heat, but I don't think I saw any data quantifying how much cooler the gun runs.

    The brass case is in the chamber for such a short time after firing, just how much heat is it transferring vs the long jet of superheated gas traversing the bore?

    I suspect marketing at work
    Schrödinger's Gat - The logical paradox which posits that a firearm, stored safe in the home, is at the same time On The Streets

  9. #49
    Senior Member Grimlock's Avatar
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    Quote Originally Posted by Mark-II View Post
    I read the bit about insulating the powder from barrel heat, but I don't think I saw any data quantifying how much cooler the gun runs.

    The brass case is in the chamber for such a short time after firing, just how much heat is it transferring vs the long jet of superheated gas traversing the bore?

    I suspect marketing at work
    I saw a breakdown somewhere. I think it was something like 20% of heat ends up in the brass. If you can assume that no more can go into the barrel than already does and the plastic is a good enough insulator, there is only one place left for it to go. A piston rifle is going to run cooler than DI.

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