What weight of pellets did they use to measure the power of AEG springs?

Discussion in 'Gun Building, Modifications & Repairs' started by OverdriveRules, Dec 1, 2021.

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  1. OverdriveRules

    OverdriveRules Member

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    OK, I know that the numbers in AEG springs relate to the firepower of the springs in meters per second, but I wonder: what weight were the pellets they used for testing? .20? .25? Something else?
     
  2. cetane

    cetane Well-Known Member

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  3. aotsukisho

    aotsukisho Well-Known Member

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    M = 0.20g
    SP = 0.25g
     
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  4. Squad144

    Squad144 Active Member

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  5. Ben3721

    Ben3721 Well-Known Member

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    More of the question is what barrel and cylinder was measured to get these numbers... and other factors like piston assembly weight and spacers like bearings.

    It's all ballpark stuff. Most the time I still end up adding spacers or cutting a coil or two off. Even batches or "identical" springs aren't the same. It's always close tho.
     
  6. OverdriveRules

    OverdriveRules Member

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    All very good answers. I just wanted some input because my CYMA AIMS does about 360 FPS with .28s, and I wanted to downgrade that a bit because even though that passed at my local field, it still seems somewhat like overkill to me.
     
  7. Ben3721

    Ben3721 Well-Known Member

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    What's the chrono requirements there?

    I shoot 340 with .28 at a field that has a limit of 400 with .20 which is almost the same joule.
     
  8. OverdriveRules

    OverdriveRules Member

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    Last I checked, it was 400 with .25s, and considering what my King Arms 1928 did with .25s and .28s, I calculate that this gun does 390 with .25s, which is good enough to pass. Still, that seems a bit hot for me.
     
  9. Squad144

    Squad144 Active Member

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    Sounds a little hot but for outdoor, isn't that the FPS you would shoot for with .25?
     
  10. wetpee

    wetpee Active Member

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    Someone else might be able to confirm this but I think that's just Prometheus being weird.
    On Brill I think they're all "MSxxxSP"
    So I believe it goes by SP rating = m/s with .25g
    Idk if they are producing springs using any other rating system at the moment.
     
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  11. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    No standards...

    Each maker just makes up a scale for their own purposes.
     
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  12. cetane

    cetane Well-Known Member

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    and all the various spring lengths and pitches as well… I just fixed up my quick change spring tester, and I threw some short little chrome plated spring which felt really soft, which I thought was something like a M85 or M90 spring, and I was shocked/surprised when my chrono was showing ~500fps/0.20’s when I tested it. I tested a m170 shs spring, and it didn’t test right. It was 490’s.. it was binding on the qc spring guide, and inside the piston body. I had to fight it off the guide.