How Do I Build a Semi-Auto Only Gearbox?

Discussion in 'Gun Building, Modifications & Repairs' started by tim_the_bear, Dec 31, 2016.

  1. tim_the_bear

    tim_the_bear New Member

    Tim Town
    I am building a ground-up DMR and decided to build my own gearbox (with a Lonex 8mm Shell), and want to know how to make it without having a full-auto option. I want to use it at American Mil Sim events, which require that DMRs are not able to shoot full-auto. I want to know how to make it so that full-auto does not work, but I don't know how. Any help with this would be great. Also, if anyone knows of a gearbox shell that does not have a full-auto switch (so that you either have the selector switch on safety or on semi-auto), that'd be great. Thanks!

  2. Spaceman7

    Spaceman7 Member

    You just have to cut off like 4-5mm of the selector plate that engages the cut-off lever. Or get a computerized mosfet that can lock it to semi only, but that's a much pricier solution.

    YouTube "how to make v2 gearbox semi-auto only" and they'll show where to cut the selector plate.

  3. Lefse

    Lefse Well-Known Member Supporting Member

    If it's an AK gearbox, or one that has a similar selector and safety mechanism you can just remove the selector plate and it'll be semi-auto only.
  4. E135

    E135 Active Member

    If you can, get out an already assembled gearbox, then observe how the parts interact when switching between full and semi. If it is a V2, you just got to remove some material to prevent part of the selector plate from pushing the cutoff lever against the small spring. It is best to understand what exactly causes the switch in order to decide what you can do to disable the undesired function, as I doubt there is a tried and true method for all gearbox designs.
  5. Airborne101

    Airborne101 Well-Known Member

    You can also drill a hole or 2 in the shell right behind the selector plate. Then JB weld a pin or 2 there to physically stop the selector plate from sliding all the way back to the FA position. This will also stop your selector switch from being in the FA position.
  6. cetane

    cetane Well-Known Member

    Markham & Stouffville, Ontario, Canada
    Just remember without a computerized trigger board, you run the risk of getting semi auto lock. To clear it you need a way to bump the motor full auto to reset trigger
  7. AirsoftSniperz

    AirsoftSniperz Member

    You can also glue a piece of something to block the selector switch itself from going into the full auto position. Maybe JB weld a piece of old credit card onto the receiver?