If you’ve ever looked at your Matrix/S&T M3A1 Grease Gun and thought, "I’d love to take this apart, but I’d also love for it to actually work again," you aren’t alone. Analog Airsofter recently tackled this project after discovering his replica was over-hopping BBs straight out of the box. Since the internet offered exactly zero tutorials on this specific model—unless you happen to speak fluent French and frequent obscure forums—this guide serves as the first English-language map for navigating the fun of a split-gearbox SMG.

The process begins with a surprisingly tool-free start, removing the stock and barrel nut, before quickly descending into a world of tiny grub screws and tension latches. This shows several quirky design choices, such as a mechanical safety that interacts with a microswitch in a fashion best described as crude but effective. The internals reveal a split gearbox where the motor and gear train live in separate neighborhoods, making shimming a breeze but reassembly a test of your patience and your ability to avoid catching wires on every metal burr in sight.

After some heavy lifting—including swapping in high-torque gears and a new motor to achieve a more historically accurate (and less whiny) chug—the results are in. While the technician had to grind down the motor cage to prevent it from sounding like a dying cat, the final product is a rock-solid replica that hits targets at 150 feet. It turns out that with enough grease on your hands and a bit of ADHD-style organization for your screws, you too can turn this quirky airsoft gun into a reliable field performer.