Semi-Auto Only

[Crono0001]

So with most fields and communities, DMRs going over a certain FPS limit requires semi-auto only.

Now the easiest way to do this would be to shave off the piece of your selector plate that brushes up and allows full auto.  Nice, free, and easy.

But, some people say that, to do it right, you'd need to equip your gun with a MOSFET.  Now, I've done some reading a la Google on MOSFETS, but I don't really understand a need for them (which probably comes from my lack of completely understanding what they do).  If someone could explain/link in laymen terms

Also, I notice with most airsoft guns (at least, with the ones on my squad), if you switch from semi to safe and to semi sometimes, there are times when the trigger is 'stuck'.  You can pull back all you want, but it won't budge (as if it's on safe).  It won't be until you go full auto that your gun engages again.  Can anybody tell me a reason for this?  Reason being, I don't want to shave my selector plate, and then find out that I need to go to full auto in order to get my gun 'un-trigger-jammed'.

[Terreus]

MOSFETs are basically an advanced trigger switch that is more efficient and durable than the standard contact pads of most AEG's. These pads can get corroded from arcing electricity and can eventually cause failures and battery issues. MOSFETs also can be outfitted with an active braking feature which regulates the spin of the motor, ensuring that with every pull of the trigger, the gearbox will cycle all the way, even if the trigger doesn't get pulled all the way. I had a MOSFET on my old CA36k and it was by far the best modification i could have put it, ROF increased, battery life extended, and i never jammed up once.

As for the trigger jams, im not sure whats going on exactly, but if its a gearbox cycling issue, in theory the MOSFET should fix it.

short version; If you're going to be modding a rifle for semi only, GET A MOSFET.

oh, and read this;

http://infectedairsoft.wordpress.com/it ... g-circuit/

[Sykinder]

The semi "stuck" problem is caused by the motor not stopping exactly every time(IIRC), and as you keep shooting on semi it starts to lose timing of gears, then the anti-reversal gets stuck on the bevel gear. Like Terreus said it can be fixed it with a MOSFET or you could take off the pistol grip, and motor and "unlatch" the anti-reversal from the bevel gear, but it will do it again.

[axisofoil]

The mechbox sticking is caused by the motor/gears coming to a rest while the semi-auto cutoff lever is in the open position, usually caused by you quickly pulling the trigger and releasing before the shot is complete. It's a problem mainly seen in V3 gearboxes.

Active breaking doesn't change this. A shot completion timer and/or microswitch will though. A mosfet isn't necessary at all for a semi-only DMR, but does make it simpler if you get a computerized mosfet such as the Extreme Fire Cheetah or Panther... as it only requires you modifying the wiring, not the selector plate, to get semi-only.

If you are worried about your gearbox lockups of this type, then you can wire in a separate button in parallel to your trigger (this applies to both mosfet controlled and standard wiring setups, although it is much smaller in a mosfet setup as it doesn't carry a large current) so that you can complete the circuit and fire a shot (this button would be full-auto only, however, if you have standard wiring, or anything lower than a computerized mosfet with a single-shot timer) in the event that your gearbox gets stuck in this position.

Sykinder's solution only works if you have a gearbox similar to a v3 where you can get to the anti-reversal from the bottom of the gearbox, such as in an AK or G36. And the solution is a solution to a "locked" gearbox (stopped firing mid-cycle, but don't have the torque/power to finish the cycle from a stop when you try to resume firing)... which as I understand it, isn't your worry, but rather the 'stuck' gearbox where switching to full-auto solves the problem.