Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

XM8: Polymer Cartridge Casings

Discussion in 'Rifle Country' started by starfuryzeta, Mar 9, 2004.

Thread Status:
Not open for further replies.
  1. starfuryzeta

    starfuryzeta Member

    Joined:
    Dec 26, 2002
    Messages:
    313
    Location:
    FL, USA
    http://www.strategypage.com//fyeo/howtomakewar/default.asp?target=htweap.htm

    What does the makeup of the case have to do with the amount of powder needed to propel the bullet?
     
  2. Third_Rail

    Third_Rail Member

    Joined:
    Jan 10, 2004
    Messages:
    4,981
    I hope that flops, I'd hate to see manufacturers switch to ????ty cases that won't hold up just because the military switched.
     
  3. Lightspeed

    Lightspeed member

    Joined:
    Mar 8, 2004
    Messages:
    9
    I've got some of these!
    They work really well.
    [​IMG]
     
  4. benEzra

    benEzra Moderator Emeritus

    Joined:
    Dec 25, 2002
    Messages:
    8,584
    Location:
    Down East in NC
    I can think of three possible reasons.

    One--under reaction conditions of 1200 degrees fahrenheit and 50,000 psi, the polymer itself could be combustible. If this is true, only the case head would be ejected when the action cycles. (Lightspeed, does the polymer case burn up when fired, or is it ejected with the brass case head?)

    Two--the polymer isn't combustible, but soaks up less heat from the burning gases than brass would, thereby leaving more energy in the combustion products to propel the bullet.

    Three--the polymer serves as insulation between the combustion products and the chamber walls, reducing heat loss and thereby leaving more energy in the combustion products to propel the bullet.
     
  5. Third_Rail

    Third_Rail Member

    Joined:
    Jan 10, 2004
    Messages:
    4,981
    More than likely, it's the third. I still don't like the idea of polymer cases, though.
     
  6. Lightspeed

    Lightspeed member

    Joined:
    Mar 8, 2004
    Messages:
    9
    Yeah, the case ejects just like a regular brass one.
    It's not hot either, when it does, you can pick it right up. I guess this might have something to do with it having less powder. It shoots just like the Winchester white box ammo, and is just as accurate.
     
  7. MLC

    MLC Member

    Joined:
    Dec 25, 2002
    Messages:
    468
    Location:
    Solebury, PA
    As if the millions of tons of other discard plastic littering the earth wasn't enough.
     
  8. SodiumBenzoate

    SodiumBenzoate Member

    Joined:
    Feb 24, 2004
    Messages:
    697
    Location:
    Bucks Co., PA
    Yes, because polymer is so weak :rolleyes:

    I believe one of Cavalry Arms' telescoping polymer buttstocks took a bullet and the bullet deflecting down into the table it was sitting on, and the buttstock still worked fine.

    Metal isn't exactly that much better.
     
  9. Master Blaster

    Master Blaster Member

    Joined:
    Dec 26, 2002
    Messages:
    4,912
    Location:
    Delaware home of tax free shopping
    But you can reload metal, and you can melt it down and reuse it to make new cases.

    Can you reload the polymer case???????
     
  10. Archie

    Archie Member

    Joined:
    Dec 31, 2002
    Messages:
    1,978
    Location:
    Hastings, Nebraska - the Heartland!
    The polymer is also probably thicker than a conventional brass case. That means the inner burn chamber is smaller in volume. A small volume requires less propellant for the same pressure level.

    I want to know if they can be reloaded without massive re-tooling on my part. Does the case mouth retain tension? What about crimp?
     
  11. Third_Rail

    Third_Rail Member

    Joined:
    Jan 10, 2004
    Messages:
    4,981
    I never said it was, but try making a stock out of the same polymer as the cases are made of. There is more than one type, and I'd wager the cases are made from the least expensive type.
     
  12. George Hill

    George Hill Member

    Joined:
    Dec 22, 2002
    Messages:
    6,842
    Location:
    Uintah Basin, UT
    Yeah, we all know how useless the idea is in shotgun shells.
    :rolleyes:

    If it means cheaper surplus ammunition on the marker - go for it. I'm not a reloader, so I don't care about that.
     
  13. clubsoda22

    clubsoda22 member

    Joined:
    Jul 16, 2003
    Messages:
    1,718
    Location:
    SE PA
    the stuff will probably be so inexpensive when it turns up as surplus, you won't care about reloading it. Of the reviews i've read about this ammo, they have all been good. Different color plastic cases will also make it very easy to distinguish different loads.
     
  14. Vern Humphrey

    Vern Humphrey Member

    Joined:
    Dec 30, 2002
    Messages:
    18,719
    Location:
    Deep in the Ozarks
    Not to be pickie, but sausatges have casINGS. Cartridges have cases.
     
  15. clubsoda22

    clubsoda22 member

    Joined:
    Jul 16, 2003
    Messages:
    1,718
    Location:
    SE PA
    who are you talking to?
     
  16. Vern Humphrey

    Vern Humphrey Member

    Joined:
    Dec 30, 2002
    Messages:
    18,719
    Location:
    Deep in the Ozarks
    Check the thread title:

    XM8: Polymer Cartridge Casings

    For a moment, I though it was all about making summer sausage.;)
     
  17. clubsoda22

    clubsoda22 member

    Joined:
    Jul 16, 2003
    Messages:
    1,718
    Location:
    SE PA
    you are being pickie :D
     
  18. Vern Humphrey

    Vern Humphrey Member

    Joined:
    Dec 30, 2002
    Messages:
    18,719
    Location:
    Deep in the Ozarks
    Reminds me of a Law and Order episode, where the bad guy was shooting people with a double-barrel shotgun.

    The brilliant detectives decided that since there were no "casings" found at the scene, he had to be using a "breech loader."

    Well, duh!;)
     
  19. Third_Rail

    Third_Rail Member

    Joined:
    Jan 10, 2004
    Messages:
    4,981
    Or... maybe a musket! Wow!

    Right, anyway, I'm all for cheap surplus ammunition, but I'm also for reloading and custom match loading. I don't want to see brass cases go the way of brass hulls (i.e. really expensive and hard to get)
     
  20. natedog

    natedog Member

    Joined:
    Dec 24, 2002
    Messages:
    2,634
    Location:
    Bakersfield, California
    Just curious, I haven't really thought of this before, but why isn't brass standard for shotgun shells? Why has plastic (so far) been used only for shotguns and not rifles?
     
  21. Third_Rail

    Third_Rail Member

    Joined:
    Jan 10, 2004
    Messages:
    4,981
    Think of how BIG hulls for shotguns are. People don't like spending a lot of money on brass.
    Now think of how tough brass is to work after a reloading. People don't like wasting a lot of time gluing wads over their shells, crimping the plastic is easier.
    Now, think of how much easier it is to produce plastic hulls compared to brass.
    Now, how about the average pressures of shotguns being fired? Not too much plastic is needed to make them safe...
    It all boils down to saving money.

    IMHO, these two aren't benefits when applied to rifle and pistol cases; I want to be able to reload, I want to have a nice firm crimp. For military use only, plastic is fine, but if the industry switches over and brass cases go away, I'll cry.
     
  22. Vern Humphrey

    Vern Humphrey Member

    Joined:
    Dec 30, 2002
    Messages:
    18,719
    Location:
    Deep in the Ozarks
    Shotgun shells (and many early rifle shells) were made of paper with metalic heads. The advantages of paper were many -- low cost, ease of manufacture, and so on. The disadvantage was paper could swell in high humidity.

    Brass shells require a different chamber -- since the interior diameter of a brass shell is larger than for a paper shell in the same gauge. The Army used all-brass shells in WWII in the tropics, but loading for guns originally chambered for paper shells was a probem.

    The development of plastic shells overcame all the disadvantages of paper, and has proven an ideal solution.

    If we were to go to all-brass shotgun shells, the interior dimension problem would affect performance, and we would gain nothing -- in fact, we'd lose in terms of cost, weather resistance and ruggedness.
     
  23. Preacherman

    Preacherman Member

    Joined:
    Dec 20, 2002
    Messages:
    13,309
    Location:
    Louisiana, USA
    Lightspeed, where did you get that ammo? Can the rest of us buy some? I'd like to put a few boxes through my rifles to get a feel for it, and see how well it works in various actions.
     
  24. Lightspeed

    Lightspeed member

    Joined:
    Mar 8, 2004
    Messages:
    9
    I got mine from a friend who's a gun dealer, I don't know wherre it's for sale anywhere else.
    I do have their web address, though=
    www.natec-us.com/products.asp
    Maybe you all can track some down from there!
     
  25. Onslaught

    Onslaught Member

    Joined:
    Jan 3, 2003
    Messages:
    1,006
    Location:
    Georgia
    So you don't want technology to move us forward and let the rest of us to have cheaper ammo just because it would inconvenience you? :scrutiny:
    (before you get offended, it was a joke)

    Besides, if polymer cases are cheaper, then you could just buy THOSE and reload them... Just think, if they're really that inexpensive, you'd never have to resize brass again! Plus, if they use less powder, you're using less powder to reload, thereby offsetting any small increase in cost of the case itself.
    ;)
     
Thread Status:
Not open for further replies.

Share This Page