Accuracy of the "Coke Can Chrono"

Discussion in 'General Airsoft Discussion' started by Esoda, Oct 7, 2012.

  1. Esoda

    Esoda New Member

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    Hey all, I'm stressing myself out over the FPS of a gun I acquired in an Evike Box of Awesome. I got the box to get a discount on a nice gun for my girlfriend who is going to be trying out the sport next weekend at a field game. I ended up with this gun: http://www.evike.com/product_info.php?products_id=37181

    Now, the product info as of now says the gun shoots 350-390 FPS. However, earlier (about up until a week after my rifle arrived) the FPS read something like 400-450 on their website. The comments also vary on the FPS. Some reviewers said there's shot in the hotter range while others in the more reasonable range.

    The issue I'm worried about is the field we are heading to next weekend has an FPS limit of 400 for AEGs. I tried the local airsoft shop but they don't have a chronograph available. So I turned to this ([ame]http://www.youtube.com/watch?v=DlKX5gpo7-I[/ame]) video by AirsoftGI to try and get a close estimate. The picture I attached shows the my results. Took four shots. One in the middle of the bottom of the can which had no issue. Then three around the edge of the can which did not penetrate. According to the video that should put it in the 350-399 range.

    My question is if anyone has verified this test to see how accurate it is. Also I'd like to confirm some myths about slightly lowering some myths about lowering FPS. I've heard that if you keep the spring coiled overnight it will lower it a bit. Do you guys think this is necessary? Will it have any harmful effects on my gun? Do I just shoot the gun on full auto then let it rest overnight to keep it coiled?

    Anyway, I appreciate any help I can get. Thanks in advance.
     

    Attached Files:

    Last edited: Oct 7, 2012
  2. Archer627

    Archer627 New Member

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    Figgington
    When I get my m4 put together, I can test the accuracy of this test for you. Just got a chrono so I may as well put it to use XD.
     

  3. Esoda

    Esoda New Member

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    Awesome I'd really appreciate that. Be sure to use a Coke Can though because I think every can is different in terms of thickness.
     
  4. Archer627

    Archer627 New Member

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    Figgington
    Well, all I have is Dr Pepper cans :/. Lol.
     
  5. S1kkguy

    S1kkguy New Member

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    London
    That can looks identical to one I did a few days ago, gun chronoed at 360fps. Looks safe to be within the 400fps limits. And yes it was a coke can.
     
  6. Knief

    Knief Moderator Staff Member

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    Ann Arbor
    No, letting your gun rest over night with the spring pulled back won't lower your FPS appreciably. It takes a while. Depending on the spring, it could be weeks or months before you see a real drop in FPS. I left a PDI 150% pulled back for about 8 months (accidentally) and lost all of 5 FPS. Overnight will do nothing.
     
  7. IHOP

    IHOP New Member

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    Rockton
    If I'm not mistaken, Coca-Cola uses Ball (Name of company) cans (You can find Ball written in italics somewhere on the can). So does Pepsico and many many other beverage companies. Most cans will be the same.
     
  8. theonlyBuster

    theonlyBuster Active Member Lifetime Supporter

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    S. Florida
    Have to agree here.

    The only inconsistencies would derive from placement of the shot from can to can. If you find the area where the aluminum sheet overlaps to make the can a fully round item, well that's going to be stronger than the rest of the can. Never the less, most guns shoot 360-420 out of the box, which is well more than enough to penetrate even the strongest portion of the SIDE of the can. The top and bottom are roughly the same.

    In short, it's a decent test to get an IDEA of velocity, but no more than that. If a chrono for a field broke and there was a Coke plant across the street, I wouldn't send a bunch of kids over to empty the cans to use to chrono guns. Granted it would make for a VERY interesting game, using a can for anything other than a very rough general idea it not the best course of action.
     
  9. Esoda

    Esoda New Member

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    Well just an update, the Coke Can Chrono actually didn't work out too well. The gun ended up shooting 430.
     
  10. echo1 vmg-74

    echo1 vmg-74 Active Member

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    Richmond
    when I did it, it was off by 20 fps