M4 build

Discussion in 'Gun Building, Modifications & Repairs' started by modeldemo, Sep 12, 2012.

  1. modeldemo

    modeldemo New Member

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    Old lyme
    I'm looking to build a cqb m4 from a stock gr 16 old version, what ideas do u have?
     
  2. Star_folder

    Star_folder New Member

    1,056
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    Lexington
    It's your build, what ideas do YOU have?

    I'd get a Lonex motor, 13:1 gears, a good piston, either lonex or SHS, and a mosfet.
     

  3. Shiftyshooter

    Shiftyshooter Learn from your mistakes. Lifetime Supporter

    10,227
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    Prague
    Take the time to spell the words properly. Rules say you must.
     
  4. alex

    alex New Member

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    Atlanta
  5. tscebu

    tscebu New Member

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    Dayton
    I'd say the SHS piston is better than the Lonex, but Lonex makes a better motor. Also, nobody mentioned a spring. SHS springs are non coated, and very high quality. I'd probably buy an 11.1v lipo and a mosfet like Star_folder said. Infected armory mosfets are high quality, but because they are self-resetting, they don't support as high a rate of fire as they could. Also, read my signature. :)
     
  6. modeldemo

    modeldemo New Member

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    Old lyme
    I'm planing on keeping the internals stock till they break, I'm more focused on the externals right now
     
  7. alex

    alex New Member

    4,794
    4
    Atlanta
    yes, for CQB, you only need to tune up the internals instead of upgrading them. 300 fps is fine. increasing ROF is optional.
    if you want to run a lipo or any high discharge battery, you can easily make your own mosfet. here's how i make mine:

    [​IMG]

    IRLB3034 mosfet, 100 ohm resistor on left, 2.2k ohm on right
    [​IMG]

    [​IMG]

    positive wire taps onto the other trigger contact. let me know if you are interested in making you own mosfets. this one works up to 14.8v DSG build.
     
  8. Mystery43_4

    Mystery43_4 New Member

    1,307
    1
    Santa Barbara
    Uhhh, was this one of your first FETs? If so, I hope you've gotten a bit better at making them lol.

    You should think about bolting onto the drain tab instead of the drain pin. The pin isn't able to handle as much current as the tab is.

    You might want to rethink your gate wire. You want to create a physical joint whenever possible, as solder doesn't hold too well under pressure. You probably won't have a big issue with breaking the joints as you don't make many of them, but it's still something to look into.

    This is how I build mine. I don't have any pics without the heat shrink, but I'll probably make one up tomorrow and take pics then. Underneath the heat shrink on the gate wire, I have the lead on the resistor and the wire twisted together creating a physical joint.
     

    Attached Files:

  9. alex

    alex New Member

    4,794
    4
    Atlanta
    here's one of my first mosfets:
    [​IMG]

    i noticed that PC board based mosfets didn't connect to the heat sink, so i started soldering the ground leg. it has been tested on my 14.8v DSG with no heat problems. but it's mostly used for 11.1v and under (less than 30amp loads). i still have a package of TVS diodes, but until i get any failures, i'll keep using my present setup. so far, i have 30 units being tested locally with no failures.

    i prefer my solders to melt and disconnect instead of smoking everything. it once saved my xyclone motor. solder melted off the motor tab before the motor smoked on a high amp gearbox lockup.
     
    Last edited: Sep 13, 2012