[Smokes]

Hi, hello I'm Smokey and I bought a C-TAC M4A1 last year tried to deck it out and broke a screw to keep the pistol grip stapled to the gearbox. I don't know what spring it was that came with it stock all I know is the thing shot 450 fps (as the retailers describe it). The gearbox looks identical to a VFC with the same trigger assembly and even a notch on the exterior of the gearbox for a working mock bolt catch.

Fast forward I decided to buy a new gearbox shell because either way I needed to put a spring in with less power to hopefully get it to 350 fps for indoor fields. So today was the day I finally gave myself a day to work with it. I watched a few videos on Youtube about disassembling and reassembling standard version 2 gearboxes, swapping springs and the works and felt I was confident for the task.

Disassembly went pretty well, initially opening the gearbox caught me off guard when the power spring pushed the cylinder out but I didn't notice any parts missing, maybe some shims but I didn't hear anything hit the floor or the walls.

Starting with the plate that engages the selector lever, then to the trigger assembly, to inserting the gears and the anti-rotation nub and finally working my way to the cylinder head, piston, tappet plate and squeezing the damn spring and spring guide back in.

I had trouble putting the gearbox back together cause the spring which puts tension on the trigger kept slipping away and I'd need to reopen it to get all that squared away.

I connected my MIAD grip to the gearbox, got out a 7.4 lipo that came with it and tested the thing out only to find the motor trying it's hardest to turn the gears but to no avail. Thinking it might be a weak battery I tried a 7.2 lipo I believe it is that came with a VAL I bought later on. Same problem.

I opened the gearbox back up thinking the piston wasn't engaged correctly on the tracks inside the gearbox and tried again. No avail. And again thinking the anti rotation nub wasn't correctly in place. I've even tried inserting the motor in the opposite direction to see if I just had it in backwards.

I'm stumped. This is my first airsoft gun ironically (well other than clearsoft wal-mart POS'), and my first time cracking open a gearbox and working on it intimately. I read another forum post with someone who has a similar issue with a lot of feedback saying the it was inadequate parts like not having a powerful enough motor or the piston being too heavy or something like that. But to me that doesn't make sense 'cause I'm downgrading to an guarder SP-90 non-linear when the stock spring is a bit shorter but has A LOT more resisting tension. If anyone has any tips or feedback, share away I'll try them one after another.