Why Plastic Cases Are a BAD Idea

Discussion in 'Handloading and Reloading' started by jski, Oct 19, 2021.

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  1. Slamfire

    Slamfire Member

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    My Dad's

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    mine

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    I can still use the C & D scales, can figure out the K, but that is about it. At some point, you have to leave old technology

    I can still balance a check book with this, finding ribbons is the hard part

    NaO2kKj.jpg
     
  2. Mark_Mark

    Mark_Mark Member

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    I could! but I prefer the healing effects of the Sun
     
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  3. Mark_Mark

    Mark_Mark Member

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  4. mcb

    mcb Member

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    Love Slide Rules, I have the two that were my fathers and I have added three more to my collection. I really want a Curta, mechanical calculator, but the price has sort of gone crazy lately. Much to the derision of my friends I did my second semester of undergrad physics with one of dad's slide rules despite having an HP 48sx calculator in my bag, still had the highest grade in the class. :D

    None the less I think polymer cases have matured a lot since I first encounter them in the early oughts. I think they could make a noticeable impact on the military if the last of the shortcoming are overcome and it seem like they are being overcome. I see a place for them in the commercial market too. What I don't see is them have a dramatic impact on the brass case ammunition market. As I have said in other thread I can still buy ammunition, brass and bullets for my 105 year Webley Mark VI the likely hood of them stopping the production of brass cases in the next 100 years seems very unlikely. This fear that new technology is going to kill old products always amuses me. There are still one or two makers still making slide rules...
     
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  5. GeoDudeFlorida

    GeoDudeFlorida Member

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    You collect slide-rules?

    My dad worked on the Atlas program and I still have his old slide rule. I used it my first year in college (engineering major) but it's just collecting dust now. These days I write code in obscure languages and build virtual environments. Boring stuff but it pays the bills - most of them, anyway. If you want it, send me an IM and I'll dig it out of the shed for you. I may even still have the original book that came with it. No promises on that.
     
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  6. jski

    jski Member

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    This is a mechanical calculator and a marvel of engineering:
    upload_2021-10-20_23-18-47.jpeg
     
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  7. Mark_Mark

    Mark_Mark Member

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    invested 25AD and capable of doing advanced mathematics

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  8. higgite

    higgite Member

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    The first calculator. Invented in the Garden of Eden.

    closeup-finger-symptom-pain-numbness-600w-1456968986.jpg
     
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  9. entropy

    entropy Member

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    Only goes to 21, 20 for females. ;)
     
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  10. jski

    jski Member

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    Guys, time for me to fess up. In my original post I stated that brass has a specific heat 2X that of steel. WRONG!

    Specific Heat Capacity of Metals Table Chart
    Metal J/(kg-K)
    Aluminum
    921.096
    Brass (Yellow) 401.9328
    Carbon Steel 502.416

    The interesting thing here is aluminum’s specific heat. Again this shows that even if a material has a higher specific heat, because of its mass density it may not carry away the same amount of heat as a part made from a denser material, e.g., plastic cases vs brass or steel cases.
     
  11. Varminterror

    Varminterror Member

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    Thermal conductivity...

    Heat capacity does matter, but it ain’t the entire package...
     
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  12. barnfrog

    barnfrog Member

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    Where's the square root button?
     
  13. mcb

    mcb Member

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    Slightly off topic into a theorectic future but what happens if /when the military were to finally successfully make and field caseless ammo and firearms. I wonder what a single stage, turret, and progress caseless reloading press looks like for the hobbyist? Instead of crimp dies we will argue about plasticizers... :rofl:
     
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  14. jski

    jski Member

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    Interesting evaluation of GD’s entry:
     
  15. Jim Watson

    Jim Watson Member

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    My 6th grade Dad thought it was amazing that I had learned how to extract a square root on paper.
    Long forgotten.

    I still have my pocket Post slide rule, the full size one likely went at The Incident.
    I started college with a K&E, a pretty lavish high school graduation present from my Aunt, largely because that was what Kip Russell had. But it was stolen and I replaced it with the more up to date Post.
     
  16. Pottimus

    Pottimus Member

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    It seems like the empties will be worth less than the steel case nobody ever picks up. Are they too toxic to melt back into kids toys. Can we legally burn them to stay warm? I call it a solution in search of a problem...
     
  17. ballman6711

    ballman6711 Member

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    Interesting thoughts. I do understand the weight savings aspect which will allow soldiers to carry more ammo onto the battlefield, but their are other positives as well. Imagine the enemy collecting the spent brass cases after a battle and reloading them, thus giving them more ammo for the next battle. This can't currently be done with plastic cased ammo.

    One negative could be what our public ranges will look like if this stuff becomes available to the public at competitive pricing. Will people bother picking it up if it has no reloading or recycling value? Most people don't bother to police their brass/steel cases where I shoot, and I just can't see them picking up their spent plastic cases either.

    chris
     
  18. Slamfire

    Slamfire Member

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    I really doubt empty brass cases were scavenged as there were much larger things laying around.

    Both in Vietnam and in Iraq/Afghanistan, exploded American ordnance, was salvaged, the explosive charges re used, or just the entire shell refused, against our people. I saw a video of Afghan Taliban filling a five gallon jerry can with the explosive charge from an un exploded American bomb. They put flowers in the thing and set it up by the road side.


    https://data.opendevelopmentcambodia.net//dataset/us-bombing-in-cambodia-1965-1975-

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    Abut 30% of American Ordnance dropped in Vietnam were duds. And I consider this a real scandal, how come the American public pays good money for contractors to make defective ammunition? Really shows the corruption of the Defense Department.

    http://legaciesofwar.org/resources/books-documents/land-of-a-million-bombs/

    One member of the gun club, a retired Colonel, told me he lost his leg in Vietnam due to a 105 mm artillery shell bobby trap. The American shell did not explode, the VC salvaged it, and he lost his leg. But at least the contractor made full profit making defective ordnance.
     
    Last edited: Oct 22, 2021
  19. Tirod

    Tirod Member

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    Colt did one of those, 6 mags in, the gas tube on a M4 style rifle was red hot, another mag caught the handguard on fire, and then the barrel started drooping and a bullet exited it near the gas port.

    The larger mass of the chamber area might be slowing it down, but it is opening up and gas does eject past the brass into the action on a self loader. Hence, dirty brass, whether a blow back, impingement or gas pistol. Also, handguards with ventilation, unlike manual actions.

    Motorcycle tuners are known to use a grease pencil and mark down the length of exhaust pipe to "tune" the length, where it stops melting is their indication the gasses have cooled - which also affects velocity of that gas. Thats where they cut the pipe. One a firearm where the barrel is hottest would indicate the maximum burn and elevated temp of the gas residue. It would diminish after that with expansion and cooling. Look to the Thompson's location of cooling rings on the barrel, similar.

    The composition of the case doesn't likely change things much at all. And not to forget, artillery and ships guns often don't use a case at all, projectile and powder bags are their thing after a certain size. Huge pieces of hot brass in a tank turret bouncing around would be an issue.

    5.56 down your neck is too. Im all for a composition case - the other benefits are real, no brass scrap, policing, sale, etc altho the reloaders will get pinched in that. No roly poly under foot in urban combat if caseless, noise, and the poly casings being less reflective and colorful, too. Reduced weight is a factor, altho anyone who's studied the history of equipping troops knows that a 40% reduction in ammo weight really means a 40% increase in loaded magazines.

    The LSAT and other advanced designs are also not using the case as the seal - a shuttle door which contains the chamber pressure is the one item I haven't seen pictured on line. Proprietary I guess.

    Sierra is loading the stainless duplex cases and selling ammo now, I like the concept for CCW carry, less to corrode. If I see those at the range I'm nabbing them.
     
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  20. GeoDudeFlorida

    GeoDudeFlorida Member

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    I'm considering tinkering with 3-D printed ammo. Theoretically, if you can polymerize the nitrocellulose (which has been done) into a stable, heat fluid compound, you can "print" smokeless powder onto the base of the bullet (also 3-D printed using something like Cerrosafe?) and make target loads directly. Priming would be the real trick, there.
     
  21. entropy

    entropy Member

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    Some tanks have ejectors where the shell goes out the back of the turret, but some don't.
     
  22. Walkalong

    Walkalong Moderator Staff Member

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    Well, it was fun while it lasted.
     
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