Daytona M4/HK416/MSK/PDW Fire Selector Cut Tutorial
This guide aims to show you the proper way to measure where to cut on your fire selector to make the SEMI-AUTO position work.
In this guide, a G&P WOC trigger box will be used. This will be 90% identical to all platforms which require fire selector modification. It is only a matter of slightly different deepness & cutting angles.
G&P WOC M4
WE M4 / HK416 /Raptor
VFC M4 / HK416 / M27
VFC Hk417 / G28
This is a G&P WOC trigger box with an uncut G&P fire selector. On SEMI position, the full auto lever (left side lever) does not drop down. This will cause the system to fire full auto on semi-fire position.
To start, press down the full auto lever with your finger (left side lever), and while pressing on it rotate the fire selector around to the SEMI fire position back and forth. Turn the switch 40 degrees counterclockwise from Semi, then to 40 degrees clockwise from semi-auto. Repeat this about 20-30 times. The goal is to allow the full-auto lever to scratch the fire selector and give you an idea of where & how much you need to cut.
You will be able to see that the fire selector was scratched by the full auto lever. Use a marker to mark the scratch so you know how much you need to cut. Make sure you mark up by one extra millimetre so the lever can move more freely.
Put the fire selector on the mill for a nice and clean cut. You can also use Dremel (with grinding or cutting wheel) to finish. Note that you don't need to cut it all the way into the factory groove. Just cut what is needed. Overcutting will cause a trigger reset problem.
Put the selector back into the receiver and turn it on SEMI fire position. Check if the full-auto lever (left side lever) falls into the desired deepness. Pull the trigger and manually press down the semi lever (right side lever with brass nub) to see if the air valve is disengaged. Then release the trigger pull and see if the trigger resets.
If any of the above procedures are not able to produce the desired result, re-measure the selector and cut it a bit more.