Explanation for semi-auto seizing
Semi-auto seizing occurs during an incomplete trigger pull. Incomplete trigger pulls is prone when the shooter taps on the trigger or pulls the trigger half way just enough for the trigger switch to connect and fire the gun. Half way trigger pulls are usually done to imitate
poor real steel firing techniques where the shooter pulls slowly -- waiting for the sear to disengage -- and releases the trigger immediately after the weapon is cycled. Since AEGs don't have sears, trigger pulls should be quick (to avoid trigger switch oxidation) and complete (to avoid gearbox seizures). The range of trigger movement should be
FULL. (A rule of thumb is to pull the trigger all the way back on every shot.)
When the trigger is pulled just enough for the
trigger switch to connect, the gun will either half crank the piston, or it will cycle and release the piston to fire a shot. After the piston has been released to fire a shot, the
sector gear continues to rotate. Underneath the
sector gear is the
disconnector cam. While the
sector gear is still rotating, the
sector gear disconnector cam rotates along and pushes down on the
cut-off lever. The
cut-off lever rotates 20 degrees (counter-clockwise) along it's pivoting axis and pushes up on the
trigger switch block. When the
trigger switch block is pushed up, it separates from the
trigger bent. The
trigger bent is located directly on the
trigger itself. The
trigger switch return spring then pulls back on the
trigger switch block and opens the entire electrical system causing the gun to stop firing. This process is normal such that the gun will only fire one shot during semi-auto.
However, since the trigger pull is done ever so slightly, not enough power is available to further cycle the
sector gear. The
sector gear will remain at it's position where the
sector gear disconnector cam continues to push down on the
cut-off lever. The
cut-off lever will be
locked in the 20 degrees position. At this point, every time you pull the trigger, the
trigger switch block will ride up the
cut-off lever like a ramp. The
trigger switch return spring will pull the
trigger switch block rearwards before the switch can connect and complete the electrical circuit to fire another shot. When the gearbox is seized, the clicking sound you hear is the
trigger switch block being pulled back and smacking against the
trigger return stop (trigger return stop: a protruding piece that's directly molded onto the gearbox. Faulty gearboxes will eventually have this small part broken due to repeated hits by the trigger switch block.)
To fix this problem, the user changes to full auto, fires a round, and returns back to semi. This works because during full auto, the
cut-off switch is no longer engaged with the
sector gear disconnector cam. The cut-off switch is rotated pass 20 degrees to 45 degrees. At 45 degrees, the
cut-off switch is raised above the
trigger switch block and can no longer knock out the electrical system.
Manchovie mentioned about using a larger battery to prevent semi-auto seizing. It's true because when excess amount of volts is used, the
sector gear disconnector cam will almost always have enough power to rotate completely and not get stuck at a position where it continues to push down on the
cut-off lever. So even if you slightly tap on the trigger, enough electricity will cause the
sector gear to completely rotate.
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