13:1 Gears in my G&P. Goal: 400fps / 30rps

Discussion in 'Gun Building, Modifications & Repairs' started by Sutro, Jul 25, 2015.

  1. Sutro

    Sutro New Member

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    Goal for my g&p m4 with a 300mm inner: 1.5j/30rps
    I have a zci 22tpa ht motor, and 16:1 gears with a sp120. I already have overspin.

    How would i cure this?
    If i shave the tooth on thr gear, will i have to shave the tooth on the piston? My gun fires 415fps right now.

    Thank you guys.
     
  2. AirsoftRyan778

    AirsoftRyan778 Active Member

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    You do not need to take a tooth off the piston. What you should do is #1 shim your motor magnets to the armature, I have a tutorial on how to take apart a motor and maekii has a vid on how to shim magnets. #2 check you cutoff lever for wear, if it is heavily worn replace it #3 shave off 2-3 teeth off your sector and get a heavier spring. Theairsofttech has a good vid on how to do this properly
     

  3. Sutro

    Sutro New Member

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    Oh ok, wow every video is different. People do it differently on other forums. 2 or 3 teeth off the pickup of the sector gear right? Or last tooth that releases the piston?
     
  4. Lefse

    Lefse Well-Known Member Supporting Member

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    Shortening the return spring for the trigger switch can help reduce overspin quite a bit IME.
     
  5. Wingman703

    Wingman703 Moderator Staff Member Moderator

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    Woah there buddy, that's serious overkill and effort just to nuke some overspin.
    First, how much overspin do you have? 3-4 teeth is nothing to be overly concerned about. If its cycling more then that, you can add some epoxy to the cuttoff cam so that it trips sooner.
    You can also use a weaker battery, but this will also reduce ROF/trigger response.
    And you can put in a bigger spring, and short stroke back down to your FPS levels. You do NOT need to removed teeth from the piston, only from the pickup side of the sector gear.
     
  6. AirsoftRyan778

    AirsoftRyan778 Active Member

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    I wasnt saying all of them, one of them is enough
     
  7. AirsoftRyan778

    AirsoftRyan778 Active Member

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    Baltimore

    Its from the pick up side
     
  8. Sutro

    Sutro New Member

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    How did you shorten yours?
     
  9. Lefse

    Lefse Well-Known Member Supporting Member

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    You cut off 2-3 coils with pliers and then bend out the last coil to make a new hook, it's quite simple.
     
  10. cascade

    cascade Member

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    Are you double cycling on semi? Probably not with the parts you have listed. Sounds like you have pre-cocking via some mild overspin. Enjoy the better trigger response...you just need a weaker battery to cycle semi a few times when youre done to get the piston to its resting position.
     
    Last edited: Jul 26, 2015
  11. Sutro

    Sutro New Member

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    San Francisco
    Yeah this sounds about right. The idea about using a weaker battery is a great idea, and I think this will solve my issue, thanks again guys.