How is it that shotshells can be made with a significant plastic component?

Discussion in 'General Shotgun Discussion' started by Squirrel, Aug 28, 2008.

  1. Squirrel

    Squirrel New Member

    46
    0
    0
    Shotshells seem to be made predominantly out of a main plastic casing and metal parts near the base. Why is this not done with rifle and pistol cartriges? Plastic is a maagnitude less expensive than brass.
     
  2. BillM

    BillM Active Member Supporter

    1,147
    1
    38
    I've seen composite 223 rifle cases, brass base and a grey plastic case.
    There is the Tround for pistol---plastic triangular case.

    I would guess that the main reasons we don't see more plastic handgun/rifle cases
    are issues with volume and pressure.
     

  3. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

    11,380
    2
    0
    Pressures are an issue as is heat in rapid fire. I have heard stories of the plastic cased .223 sticking in chambers. OTOH, the plastic case will insulate the barrel/chamber from some of the heat of the burning propellant so it may not get as hot. The makers of the plastic/metal hybrid .223 are out of business. Maybe because they could not sell and make a profit. Maybe because they made junk. I don't know.
     
  4. c3shooter

    c3shooter Administrator Staff Member

    21,452
    587
    113
    Shotshells and rifles have a different order of magnitude of pressures in the chamber. A rifle cartridge is supposed to EXPAND and grip the sides of the chamber, then SHRINK back, so that it can be extracted. Plastic just does not do that as well as brass. Steel does better than plastic, not as well as brass. And yes, there have been experiments to use other things- like leather and cardboard (see the Marston cartridges from the mid 1800s). And FWIW, I ahve a few ALL PLASTIC shotshells in my collection- the extactor has a tendency to rip thru the plastic rim, so they did not catch on- but since they are translucent, they are kinda neat- you can see the powder, shot wad, shot cilumn, etc. Think the more common brand of these was Wando.
     
  5. cpttango30

    cpttango30 New Member

    13,934
    4
    0
    Shot shells are filed with fast burning powders. Rifle cartridges are filled with slow burning powder. I have seen some plastic 223 rounds but I am not putting them in my rifle. Sorry Can you imagian trying to scrub out melted plastic from the working of a rifle. yah I ain't doing it.....
     
  6. Squirrel

    Squirrel New Member

    46
    0
    0
    Don't some pistols use fast burning powder?
     
  7. cpttango30

    cpttango30 New Member

    13,934
    4
    0
    yuppers That is why many of us use shotgun powders in our pistols. I use only titegroup in my 45acp. That was devloped as a 12ga target load powder.

    I think the problem with plastic in a pistol is in the semi auto world you need some force to hold that bullet in the case and not allow it to move back into the case under recoil. Having that happen would cause malfunctions and or KABOOOOOOOM's add that to the fact that Pistol esp semi-auto pistols have so many different chambers supported unsupports flutted ect...... But in a rifle like the 700 the case is fully supported and covered by the 3 rings of bolt, barrel, and action.
     
  8. Mark F

    Mark F New Member Supporter

    2,918
    0
    0
    I really can't contribute much to the topic regarding plactic shells, but I also use TITEGROUP shotgun powder in "some" pistol loads. It works very well in my 45LC.
     
  9. Squirrel

    Squirrel New Member

    46
    0
    0
    But would it not be possible to make a pistol with cappability to fire plastic ammunition designed specificaly for that gun in order to make the cost of ammunion for that gun much less than what it otherwise might have been?
     
    Last edited: Aug 29, 2008
  10. cpttango30

    cpttango30 New Member

    13,934
    4
    0
    No not really why well because you have to pay a whole bunch of smart guys to figure out a way to fix the problems that it would have then you have to either add another tooling line or retool a line you have. So in the end it was cost much more than just making brass, alum, steel cased ammo...

    It is not so much the heat as is the internal ballistics and the other smart guy stuff. Smart guys make big big buck and to have a bunch of them working on a project that will more than likely fail to get off the ground is not a good business practice. They want to make money not lose it.

    OK Remington tried that with their etronx rifle and its electronic primers yeah didn't work because the rifle cost $1000+ and the ammo was well over $100 the last time I seen it being sold. $100 for 20 rounds of 22-250 even rich guys are not that damn stupid. Now if you have that rifle you can't shoot it at all because, the last time I looked no one makes ammo for it. But everyone makes 22-250, 308 and 30-06.

    Just like the 22 jet and Smith & Wesson. It failed and failed hard.

    It is better to make a pistol or rifle to fit existing ammo than to reinvent the wheel to fit the wagon.

    I understand your thinking because plastic is cheaper than brass but the bottom line has much more than the price of the raw materials involved.
     
  11. Squirrel

    Squirrel New Member

    46
    0
    0
    I see your point. Thanks for the info.
     
  12. hubel458

    hubel458 Member

    312
    0
    16
    Pressure is the difference. Shotguns are generally loaded
    from 7000 to 15,000 psi in plastic. Rifles are loaded from about
    30,000 to 70,000 psi in brass cases. Plastic can't work at
    those pressures.In our 12GA FH testing we run plastic cases
    higher up to 23,000, but they don't extract good.
    But we als found in our testing that the thin balloon-
    headed 12ga brass cases, that are being made and used a lot
    for low pressure blackpowder shooting and competition
    wouldn't take as high of pressures and expanded more
    than good plastic 12ga cases..Ed
     
    Last edited: Sep 6, 2008