Feel free to contribute to the guide with your own experiences. I’ve documented all of the roadblocks and tricky bits that I encountered whilst performing this upgrade.
The M4 was running an alloy buffer tube at the time I of the upgrade. Aside from that, it was mechanically standard.
The Mag terminal block necessary for this upgrade was purchased from Chainsaw. I took the advice of others to get an alloy selector switch and hybrid nozzle from GBA.
It’s a refreshing change to work on a blaster gearbox that is not held together with self-tapping screws. Anyway, start by removing the spring, using an 8mm hex key. Work your way around the box and remove all the other gearbox screws with a Phillips screw driver.
Here’s what’s inside…
Here’s the AOE of the piston and sector gear…
The seal was already good with the standard o-ring but I swapped it out anyway. Sticking with the greens for now…
For this build I wanted to install the Easyfet V2 so I unsoldered the trigger block and removed the standard wiring harness to make way for my own…
The screw I removed from the blowback feature was used to affix the terminal block to the gearbox.
Now you can measure up wiring for the terminal block…
Routing it through the trigger block and down to the motor.
Solder the trace side of the wire to the positive terminal, which is the terminal closest to the trigger. I ended up cutting down the solder pads so the wire didn’t protrude wider than the terminal block… but I failed to get another pic
Normally you’d splice the positive into the trigger block but since I’m running the Easyfet I spliced both wires further down near the motor. Heatshrink and hot glue or areldite does a great job at keeping everything where it needs to be.
Before closing up the gearbox I swapped out the nozzle for a hybrid nozzle from GBA which produced a better seal with the standard Wells T-Piece.
Time to fit the gearbox into the receiver. It’s a tight fit at the best of times, but to give yourself some wiggle room you can remove the lower T-Piece from the receiver before fitting.
Lastly, we need to trim the magazine release clip down by 1.5mm so the magazines don’t drop out during pew pew. So from this:
That’s about all the little tricks needed to fit the APS box to your Wells M4.