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Determining the Amount of Gases

3_47Inf3_47Inf Member Posts: 133 ✭✭✭
edited December 2003 in Ask the Experts
Can someone help me with a math formula I cannot seem to find?

I am trying to find out how to determine how much gas is expelled during a round being fired.

I know there are people here much smarter than me in this and I am glad for their help.

Thanks in advance
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Comments

  • trstonetrstone Member Posts: 833 ✭✭✭✭
    edited November -1
    Jeez, I dunno---I think one approach *I* would take is to determine the stoichiometry of the combustion reaction that takes place when the powder is ignited, then calculate the amount of the various gases thereby produced based on the mass of powder in the cartridge. The thing is, you'd have to know the chemical composition and combustion products of the particular powder to do so---thus, it might be simpler to phone up the ammo maker and ask him/her if they'd have information on cartridge gas production to begin with.

    Sorry...I realize that this has been no real help....
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  • 3_47Inf3_47Inf Member Posts: 133 ✭✭✭
    edited November -1
    Thanks, [:)]

    I know it is a tough one, but I also know that it is possible. I was hoping one of our experts could help.
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  • Colt SuperColt Super Member Posts: 31,007 ✭
    edited November -1
    For all intents and purposes, it can't be done.

    Variables would be amount of powder, primer used, barrel length, type of powder, ambient conditions... on and on...

    I sense another question behind this one, Grasshopper. What are you trying to conclude?

    From, Zen-Third-Eye, Doug

    God Bless America and...
    NEVER Forget WACO
    NEVER, EVER Forget 911
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  • taperloctaperloc Member Posts: 420 ✭✭✭
    edited November -1
    Hello 3_47Inf,
    I don't have an answer, but I would try the NRA. They use to cover stuff like this way back in the 1960's & 70's. It's the only place I can think of for a definitive answer, other than this forum of course, that would be able to help.
    Taperloc
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  • rsnyder55rsnyder55 Member Posts: 2,526 ✭✭✭
    edited November -1
    Just a WAG, but couldn't you start by taking the chamber pressure and then try solving it as a hydraulic problem? I know fluids cannot be compressed, but it may get you in the ballpark.
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  • Colt SuperColt Super Member Posts: 31,007 ✭
    edited November -1
    That seems sensible, but barrel length and primer would determine unburned powder. It's doable as a theorical math question, and not a very hard one, at that. It only becomes difficult if you are dealing with the "real" world.

    I still bet that there's another question behind this one.

    God Bless America and...
    NEVER Forget WACO
    NEVER, EVER Forget 911
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  • gunnut505gunnut505 Member Posts: 10,290 ✭
    edited November -1
    I, too sense another use for the information, but will try to get you close.
    Get an empty bread bag. Tape it over the end of the barrel. Fire one round. Did the bag fill to bursting? If not; calculate the volume of the bag-that's your answer.

    If you know it all; you must have been listening.WEAR EAR PROTECTION!
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  • 3_47Inf3_47Inf Member Posts: 133 ✭✭✭
    edited November -1
    LOL

    Gunnut, that is one way to do it. LOL Thanks.

    Doug, there is some other things behind this, but more of thoughts in the open and tinkering. Some things that I have been reading had be begin to wonder just how many cubic inches of gas are actually released from a round, which got me thinking about there being a way to measure the various rounds, which got me thinking I am surely not the only one to ever wonder this, which got me thinking that someone has to know these things when they design a barrel, which got me thinking that the experts for that would be on this forum.

    I just wondered how many cubic inches of gas would be released by a round and figured that someone would know the formula.

    Maybe I have too much time on my hands to ponder the trivial. LOL
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  • Colt SuperColt Super Member Posts: 31,007 ✭
    edited November -1
    OK... I don't know how to math it out, but my friend Archimedes, has a way to do it, for real.

    Fill a container to the brim with water. Place it in another, larger container. Cover both with Saran Wrap. Remove the bullet from the test round, or load up your handload without a bullet. Cover the open cartridge with Saran Wrap. Puncture the wrap over the smaller container with the barrel, fire the weapon into the water. The water that escapes into the larger container should equal the volume of gas emmitted.

    Kind of hokey, but should be reasonably accurate.

    Whatcha think?

    God Bless America and...
    NEVER Forget WACO
    NEVER, EVER Forget 911
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  • WarbirdsWarbirds Member Posts: 16,927 ✭✭✭✭
    edited November -1
    By the way Archimedes' is the greek philiousipher who determined the theory of displacement. If you were exact enough it would work. Brilliant idea dad.


    R/

    Dave


    How different the world would be if we could consult the veteran instead of the politician. - Henry Miller
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