Featured How long does it typically take to fill an airsoft revolver with gas?

Discussion in 'Gas Powered Guns' started by OverdriveRules, Apr 19, 2021.

  1. OverdriveRules

    OverdriveRules Member

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    So, I've had a Tokyo Marui S&W Model 19 for a few months now, but it wasn't until recently that I found a viable source of 134a that was compatible with this duster adapter I got. Anyways, I've been curious about how long it should take to fill the gun with gas because the only information on gas filling that I can find pertains to semi-auto mag-fed pistols.
     
  2. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    It is never time based and it's not that simplistic. Time filling is incorrect.

    Example: If your M19 is 90 degrees to the touch because you left it sitting in the sun and the H134 was left in a cooler at 35 degrees, it would take about 15 minutes to fill that M19 and this is due to the change in temp over that time.

    Thus, what you need to know is the Ideal Gas Law.

    PV=nRT - Pressure, Volume, number of molecules, R Constant, Temperature (notice this equation has no time variable in it. A simplistic example is like filling the gas tank in your car, do you count when you fill your car with gas?)

    If both sides of the equation is equal, you are at equilibrium.

    If one side is higher than the other, gas particles will move in the direction of the "lower" number.

    That is why when you fill the receiving gas reservoir you have to "chill" it. Either buy immersion in a cold environment or by dissipating heat off by venting gas from the mag (this is also why CO2 is a terrible airsoft gas for rapid fire...)

    So, you chill the cylinder and then you hold the nozzle on the reservoir until the gas is "fully" transferred. How long it takes depends on the temperature gradient between your fill source and the receiving reservoir.

    You can also hear a hiss if you put your ear near the gas bottle as it filling. When the hissing stops, give the setup a shake and that will top off the reservoir. Now you know it's "full".

    Depending on the temp gradient, it can as fast as a few seconds...

    But, this all changes with a mag that has a siphon tube. The tube will reduce the fill time.
     
    Last edited: Apr 19, 2021

  3. OverdriveRules

    OverdriveRules Member

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    Very interesting stuff. I'm now considering refrigerating both pistol and gas before a game...that is, unless you have a better suggestion.
     
  4. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Just the pistol, gas should be 30 degrees warmer than the reservoir to enable a fast transfer. Also if you immediately reload the M19 after use, it should take a gas fill better too.
     
  5. OverdriveRules

    OverdriveRules Member

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    10-4!
     
  6. GrimWolf0770

    GrimWolf0770 Active Member

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    Yes I'm finding filling gas guns is a bit of a pain, too bad it not as easy as co2 ,but gas much more friendly when shooting at people.( most of the time)
     
  7. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    It's all the same principle, just due to the thermodynamic nature of CO2 it's easier to chill the receiving reservoir.
     
  8. GrimWolf0770

    GrimWolf0770 Active Member

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    There he goes throwin big words around again. : P
     
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  9. kengrant

    kengrant Member

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    griffin
    I have found that if you chill a mag too much and fill it when it is too cold you will be way over pressured when the mag warms up . It will have too much pressure and you can not depress the discharge valve .
    I had this to happen several times and had to chill the mag down a little before I could use it .
     
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  10. gunnerk19

    gunnerk19 Active Member

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    I've seen this back in my paintball days with CO2 tanks blowing out their rupture discs because the pressure was too much. Was really bad if you happened to have a gun using the CO2 tank as a stock and the thing goes off right next to your face.
     
  11. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    You can also do a manual release. Just give the release valve a few taps to bleed off some gas.

    However, that issue is mitigated with better Mag designs (TM, KSC, VFC) with siphon tubes and internal baffles over the cheaper made mags (China, WE)...
     
  12. kengrant

    kengrant Member

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    griffin
    I tried using my finger to push in the valve but always let out to much gas and cooled the mag down even more . I have not tried tapping it with something because I might make a mistake and miss due to my shaking hands . It only takes a couple of minutes to chill them down a little .
    All my mags are KSC or KWA ones and I had this overcharge problem with both .
     
  13. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    The KSC Unit has a siphon tube. The KWA units do not. You wouldn't know which you got until you open them up.
     
  14. GrimWolf0770

    GrimWolf0770 Active Member

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    So are say a Usp or vs61 from kwa deffer from a ksc of the same kind .?
     
  15. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    In a few ways potentially, yes.

    Japan Spec (J-Spec) or Taiwan Spec (T-Spec/NS2/S7) is the determining factor.

    The J-Spec models have a FPS cap, where you can't drive them beyond 340 fps very easily.