Polymer shell casings for .308

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  • Skipjacks

    Ultimate Member
    So yeah...plastic shell casings.

    https://www.thefirearmblog.com/blog/2020/01/29/shot-2020-true-velocity-and-sierra-bullets/

    When I saw the article my first reaction was "WTF?"

    But after reading it...it's interesting if nothing else

    They say the plastic casing reduces heat transfer to the power so you are less likely to get a cook off.

    Also they are lighter so you can carry more, though I can't imagine it's that big of a difference as the powder and projectile is the same.

    I feel like you could break a shell easier though if you had a misfeed or something

    I dunno...I can wrap my brain around this

    Thoughts?
     

    Skipjacks

    Ultimate Member
    If it was mass produced I have to think it would be cheaper

    That will be the determining factor of if it has market value

    I'm not a reloader so I can't tell you how what percentage of a bullet cost is in the shell casing. But if you bring the overall cost of ammo down by say...25% and these feed reliably....they will overtake brass quickly.

    Plus....it gives governments another thing to hate and ban. And I do enjoy keeping those people on their toes trying to catch up
     

    Doco Overboard

    Ultimate Member
    I think more in terms if it can get more people shooting more often its not a bad thing. Right now the only drawback I can think of is for someone like me that uses a lot of pre-Saami stuff is how well it fire forms to a non standardized chamber.
    I also wouldn't expect polymer casings to be made for a wide range chamberings either, just the popular ones. The other side of that coin however is a lot of obsolete stuff has a rimmed case due to wide differences in metallurgy so they could also be a boon to some effect.
     

    Robertjeter

    Active Member
    May 11, 2018
    460
    Eastern Shore, MD
    I actually have some of these in 5.56. My cousin was involved with JSOC and they were testing them, he gave them to me. They never saw the field, but I have a few hundred rounds to play with.


    Sent from my iPhone using Tapatalk
     

    erwos

    The Hebrew Hammer
    MDS Supporter
    Mar 25, 2009
    13,866
    Rockville, MD
    If cost can come down and it helps reduce heat transfer, that's cool, but the real driver is weight.

    There is a pretty big push by the US military to get polymer ammo working right so they can cut back on weight requirements. A lot of the focus is on heavier stuff like 7.62 and .50cal since the ammo often contributes significantly to vehicle load. In the case of something like a transport helo, the difference between polymer and brass case can be the difference between loading one more person or not.

    It is not hard to imagine a future where infantry weapons are using something like the 6.8 with the Sig hybrid case design to eke more performance out of ammo they're carrying, where the successors to 7.62 and .50BMG - I think they're looking at a 338 cartridge of some sort - will be optimized to polymer cases.
     

    Skipjacks

    Ultimate Member
    Lower weight makes them viable for military use

    But they need to be lower cost to be viable for commercial use

    If I take 100 rounds to the range it doesn't matter if I can shave 1 pound off the total weight of my bag. But shaving $10 off the cost of the rounds would get my attention

    In the field I don't care if they cost MORE. Just make them lighter.

    Cheaper AND lighter? They will replace brass entirely within 5 years
     

    Topher

    Ultimate Member
    MDS Supporter
    Sep 8, 2008
    4,817
    Fredneck
    Did I miss it??? Has anyone talked about accuracy and consistent performance?
    That is what a lot of casual shooters look for.
    Going to the range is NO fun if you can't consistently hit what you aim at.
     

    Alan3413

    Ultimate Member
    Mar 4, 2013
    16,926
    Gov would love to push this to the civ market. Make brass obsolete and reloading will die a natural death. Much easier to control ammo supply if specialized equipment is needed to make them.
     

    Skipjacks

    Ultimate Member
    Gov would love to push this to the civ market. Make brass obsolete and reloading will die a natural death. Much easier to control ammo supply if specialized equipment is needed to make them.

    It's plastic.

    3D printers, injection molds, etc....all things that are relatively easy to use to make your own casings.

    The hardest part is getting the chemical structure of the polymer right so it is both rigid enough to be durable but not so much that it shatters under pressure.
     

    Uncle Duke

    Ultimate Member
    MDS Supporter
    Feb 2, 2013
    11,667
    Not Far Enough from the City
    If it was mass produced I have to think it would be cheaper

    That will be the determining factor of if it has market value

    I'm not a reloader so I can't tell you how what percentage of a bullet cost is in the shell casing. But if you bring the overall cost of ammo down by say...25% and these feed reliably....they will overtake brass quickly.

    Plus....it gives governments another thing to hate and ban. And I do enjoy keeping those people on their toes trying to catch up

    Oh, I think we'll have brass for a while yet.

    No doubt that, if mass produced and cost effective, the military value of light weight polymer is huge. Crossover commercial potential with these same mass produced rounds for civilian shooters of common military driven examples could prove huge as well.

    But there's most definitely a flip side. These cases are currently worthless to a handloader. And there's a lot more out there than 5.56 and 7.62. Or even within cartridges, more than 55 and 62 and 147 and 175 grain of certain bullet configuration.

    Even if cases could be produced less expensively, and could typically be made so precisely as to outshoot say Gold Metal Match?
    While handloaders tend to be about precision and price both, what these polymer cases can't offer at any price, is the multi-faceted versatility inherent to handloading. Versatility that starts with reloadable cases.

    Now one day, who knows? Maybe they fix that piece as well.
     

    Skipjacks

    Ultimate Member
    Oh, I think we'll have brass for a while yet.

    No doubt that, if mass produced and cost effective, the military value of light weight polymer is huge. Crossover commercial potential with these same mass produced rounds for civilian shooters of common military driven examples could prove huge as well.

    But there's most definitely a flip side. These cases are currently worthless to a handloader. And there's a lot more out there than 5.56 and 7.62. Or even within cartridges, more than 55 and 62 and 147 and 175 grain of certain bullet configuration.

    Even if cases could be produced less expensively, and could typically be made so precisely as to outshoot say Gold Metal Match?
    While handloaders tend to be about precision and price both, what these polymer cases can't offer at any price, is the multi-faceted versatility inherent to handloading. Versatility that starts with reloadable cases.

    Now one day, who knows? Maybe they fix that piece as well.

    I don't think reloading is nearly as popular as factory ammo.

    Go to any Bass Pro Shop. There are 3 aisles of various factory ammunition and a small corner of one aisle for reloading supplies.

    I know reloaders tend to ONLY reload as they get into it and the reloading itself becomes as big of a hobby as shooting. So I'm sure that to a reloader it seems like reloading is a huge thing. You hang out with other reloaders and talk about reloading so it seems like a huge thing but I think reloaders are a small percentage of the overall ammo market.

    If I am correct the market will side with cheap over reloadable. Factory ammo will drop in price and reloading costs will go up because brass won't be as mass produced. (Primers and bullets will still be mass produced, just not she'll casings)

    There will still be a market for brass because of reloaders because reloaders won't give up reloading and will be happy to spend the money. But the price will go up

    I have ZERO stats to back this up. So if you can provide some real data on the number of reloaders vs the number of "new in box" buyers I'dd be interested in seeing it. I am making this up on a hunch and my own observations as someone who doesn't reload
     

    Skipjacks

    Ultimate Member
    I have a few rounds of .308 a friend gave me as a curiosity. If I can find them I'll post a pic.

    I'm curious how durable they are

    Are they hard so you can't squeeze them? Or is the polymer flexible?

    If it's flexible I fell like they could get jammed more

    Do you think they would stay intact if a bolt closed on the side of a casing that didn't feed? Or do you think the bolt would crack the casing and let the power spill out?
     

    Alan3413

    Ultimate Member
    Mar 4, 2013
    16,926
    It's plastic.

    3D printers, injection molds, etc....all things that are relatively easy to use to make your own casings.

    The hardest part is getting the chemical structure of the polymer right so it is both rigid enough to be durable but not so much that it shatters under pressure.

    You're assuming it's a unibody case. Most polymer cases I've seen have a metal base bonded to the plastic. You'll need specialized equipment to bond metal to plastic so it won't separate on ignition.

    The polymer will be proprietary, and it's unclear if it can be worked into filaments or whether it needs to be injection molded under conditions of temp and pressure that are out of the budget to the home reloader.
     

    Uncle Duke

    Ultimate Member
    MDS Supporter
    Feb 2, 2013
    11,667
    Not Far Enough from the City
    I don't think reloading is nearly as popular as factory ammo.

    Go to any Bass Pro Shop. There are 3 aisles of various factory ammunition and a small corner of one aisle for reloading supplies.

    I know reloaders tend to ONLY reload as they get into it and the reloading itself becomes as big of a hobby as shooting. So I'm sure that to a reloader it seems like reloading is a huge thing. You hang out with other reloaders and talk about reloading so it seems like a huge thing but I think reloaders are a small percentage of the overall ammo market.

    If I am correct the market will side with cheap over reloadable. Factory ammo will drop in price and reloading costs will go up because brass won't be as mass produced. (Primers and bullets will still be mass produced, just not she'll casings)

    There will still be a market for brass because of reloaders because reloaders won't give up reloading and will be happy to spend the money. But the price will go up

    I have ZERO stats to back this up. So if you can provide some real data on the number of reloaders vs the number of "new in box" buyers I'dd be interested in seeing it. I am making this up on a hunch and my own observations as someone who doesn't reload

    Reloaders are without a doubt a small segment of shooters overall. Might be 1 in 20 or thereabouts, if I had to take a guess, and that is strictly a guess. If you add hunters into the mix, as in hunters who aren't also shooters and thus they purchase comparatively minimal ammo, it's quite possibly a smaller percentage still. Reloaders do however, buy a disproportionate shit ton of product.

    Beyond reloaders though, it is said that the average firearms owner spend is less than $300.00 per year, per market analyst Southwick. The real volume usage is military obviously. Next is the avid shooter.

    No doubt also that cost will factor heavily into the success of polymer. I have no idea what the cost would be for a polymer manufacturer to produce molds for the many available cartridges on the market today. But my guess is that the cost is quite significant, especially when you take into account competing against industry giants using existing brass tooling, some of whom also manufacture the other components, and can provide for cartridges with comparatively minimal sales. What you might even see in response to an influx of polymer is the price of brass cases actually coming down. When you think about it, 9mm and .223/.556 as well as 22LR are your comparatively inexpensive cartridge choices today. They are also your volume choices.
    Neither steel nor aluminum have been cost efficient enough to replace brass here. Brass cases, with the volume examples I mention, breaks out in comparison to the other 3 components of a cartridge, to be comparatively a very cheap cost, when compared to other lesser volume cartridges.

    Very interested to see what happens here. But for the foreseeable future at least, I see polymer as the niche product, rather than the other way around. Of course, I could be wrong.
     

    Skipjacks

    Ultimate Member
    You're assuming it's a unibody case. Most polymer cases I've seen have a metal base bonded to the plastic. You'll need specialized equipment to bond metal to plastic so it won't separate on ignition.

    The polymer will be proprietary, and it's unclear if it can be worked into filaments or whether it needs to be injection molded under conditions of temp and pressure that are out of the budget to the home reloader.

    You know what? This is all too complicated.

    I'm getting a blunderbuss

    You have old junk? You've got ammo!
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    So yeah...plastic shell casings.

    https://www.thefirearmblog.com/blog/2020/01/29/shot-2020-true-velocity-and-sierra-bullets/

    When I saw the article my first reaction was "WTF?"

    But after reading it...it's interesting if nothing else

    They say the plastic casing reduces heat transfer to the power so you are less likely to get a cook off.

    Also they are lighter so you can carry more, though I can't imagine it's that big of a difference as the powder and projectile is the same.

    I feel like you could break a shell easier though if you had a misfeed or something

    I dunno...I can wrap my brain around this

    Thoughts?

    It’s about 30% less weight. Brass is heavy. There is increased accuracy because of the precision the case can be made and uses slightly less powder for the same muzzle velocity, again due to the ability to shape the casing interior in a way beneficial for combustion of the powder. There are a lot of wins for it.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    Reloaders are without a doubt a small segment of shooters overall. Might be 1 in 20 or thereabouts, if I had to take a guess, and that is strictly a guess. If you add hunters into the mix, as in hunters who aren't also shooters and thus they purchase comparatively minimal ammo, it's quite possibly a smaller percentage still. Reloaders do however, buy a disproportionate shit ton of product.

    Beyond reloaders though, it is said that the average firearms owner spend is less than $300.00 per year, per market analyst Southwick. The real volume usage is military obviously. Next is the avid shooter.

    No doubt also that cost will factor heavily into the success of polymer. I have no idea what the cost would be for a polymer manufacturer to produce molds for the many available cartridges on the market today. But my guess is that the cost is quite significant, especially when you take into account competing against industry giants using existing brass tooling, some of whom also manufacture the other components, and can provide for cartridges with comparatively minimal sales. What you might even see in response to an influx of polymer is the price of brass cases actually coming down. When you think about it, 9mm and .223/.556 as well as 22LR are your comparatively inexpensive cartridge choices today. They are also your volume choices.
    Neither steel nor aluminum have been cost efficient enough to replace brass here. Brass cases, with the volume examples I mention, breaks out in comparison to the other 3 components of a cartridge, to be comparatively a very cheap cost, when compared to other lesser volume cartridges.

    Very interested to see what happens here. But for the foreseeable future at least, I see polymer as the niche product, rather than the other way around. Of course, I could be wrong.

    Steel cases, brass FMJ is about 3-4 cents a round less than brass cased. It’s niche because not a lot is made. Most is bimetal jacketed steel cased ammo.

    The casing is about half the cost of a 5.56/.223. More than that for a 9mm.
     

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