S&T PP-19 Bizon build

Discussion in 'Gun Building, Modifications & Repairs' started by Joniden, Sep 19, 2015.

  1. Joniden

    Joniden New Member

    212
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    Glendale
    Hello airsoft society. I just bought a S&T PP-19 Bizon the other day and I originally wanted to simply do some rewiring, connect it to deans and use it as a CQC gun. Well turns out it shoots over 420FPS! So I have to go in and add a weaker spring. While I'm at it I want to beef it up a bit and have it shoot 330-350fps using .2s and about 15-20RPS on a 7.4V lipo. In my tests using my 7.4V lipos, the RPS is very weak so the motor needs a replacement too. So I am not making a BB hose, just something solid that I can take to CQB games and not worry about anything breaking.

    So as the reader can see, so far the main replacements will be the spring and motor. Now my two main questions are this.

    1. Since I am building a relatively weak build. Do I need to do all the mods such as AOE, cylinder radiusing, mosfet, swiss cheese the piston etc.?

    2. Am I going to run into any troubles by simply adding a weaker spring? I remember someone saying that by adding a weaker spring, I may run into problems with the piston and sector gear. Any word on that?

    I do plan on this being my thread to show how I got my gun from stock to what I want it to be and I hope that everything turns out.

    Edit 1: I don't want to replace any parts unless I have to.
     
    Last edited: Sep 19, 2015
  2. axlej11

    axlej11 Active Member Supporting Member

    1,937
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    Freeland
    1; AOE should be corrected regardless of what you're doing. Same goes for radiusing. These are longetivity mods and will save your gun in the longrun. If youre using a 7.4, you don't need a mosfet. Still good to have, but not needed. Swiss cheesing is unneccessary for this type of build.

    2; Not sure where you heard that, but adding a weaker spring should give you no problems as long as you know what youre doing.

    Shim, correct AoE, radius, regrease, all of that should be done for longetivity. 15-20 rps is a very achieveable and easy goal. Most stock setups achieve this.
     

  3. Joniden

    Joniden New Member

    212
    0
    Glendale
    But let me ask you. In your opinion, for the build I want to build, other than the replacement of the motor and spring, S&T internals are ok enough that nothing else needs replacement? Or the gears suck that much also.
     
  4. axlej11

    axlej11 Active Member Supporting Member

    1,937
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    Freeland
    I dont have much experience with an S&T. It should be able to hold up once you install the new parts. If it can handle a spring that puts out 420 fps, it should handle a weaker one no doubt.
     
  5. Joniden

    Joniden New Member

    212
    0
    Glendale
    Sweet! Thanks for your input. Now to start my research, get the parts and start modding this gun out.
     
  6. axlej11

    axlej11 Active Member Supporting Member

    1,937
    24
    Freeland
    No problem. Please update on the build status!