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Old June 18th, 2006, 17:54   #1
Raygis LasVegas
Join Date: Dec 2002
Location: Toronto
Semi-Auto Seizure Explained ( trigger glitch )

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.


AEG upgrades & repairs: $25/hr
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