Piston locked back on a Scar Gearbox, Hopefully Urgent Help Please. Thanks =)

[gerardcb]

Hi guys!! I upgraded a DBoys Scar.

I tried to fire the gun and the piston locked back and got stuck in the back.

Upgrades put in the gearbox:

- Matrix High Performance Magnum Airsoft AEG Motor - Long Type

- "Matrix" Steel CNC "Low Noise" Airsoft AEG Gear Set (High Torque) / 100:300

- Matrix Full Steel Teeth Polycarbonate Piston w/ for Airsoft AEG Gearbox

- Matrix Element Silent Piston & Cylinder Set for V.2 Gearbox.

- Matrix Element Ball Bearing Vortex Spring Guide for V.2 Airsoft AEG Gearbox

- Matrix PDI Type 260% / M130 Irregular Pitch Airsoft AEG Upgrade Spring (450~520 FPS)


Problem: I fired the gun and the piston got stuck in the back and did not release.

Suspects:

- Motor Plate Screw does not tighten, therefore motor plate is a little bit loose. Just a little.

- Shimming? I took so much time and effort to shim it. But it has diagonal teeth on the gears so I believe that requires a much more precise tuning?

- I did not have silicon oil present, so I used silicon oil Gear lubricant in the places where normal silicon oil is needed.

- Battery. I used an 8.4v mini for the first trigger pull. That probably is the cause of the piston locking back, but even with a 10.8v, it did not unlock.



Any other ideas?

Thanks!!!!!

[Styrak]

you used a 10.8v what to try to unlock it? Mini? Still might not work.

Get a 8.4v or 9.6v large battery.

[FACE]

Did you dry fire the gun or was the gun loaded when you fired it. The reason I ask is I just went through the same problem with mine where it jammed up and th piston was locked back in the loaded position.

Turns out there was a broken split bb in the piston. Half was in the piston the other half was jammed up in the tapit plate.

Hope this helps.

[coach]

Open it up carefully. Put it in a bag or a box to avoid parts from flying everywhere. This is one instance where I love not having an AR latch (ASCU upgrade - pull motor = spring release) or have the modify AR latch installed to release the spring.

You can also try to release the AR latch manually through the gearbox openings.

Fully charge your battery next time and don't use them after you notice signs of a depleted battery. A higher voltage battery won't release the piston unless your motor can turn with that much resistance which only few of can.