HELP gearbox fitting inside M4 body
 

Ok so just for a bit of info I've been rewiring my gearbox to work from the rear. and that was completed last night unfortunately while fitting the gearbox back into the gun I snapped the Fire selector plate. I have a new fire selector plate and have fully assembled the gear box again. but after getting the gear box back into the gun this time my gun wont change from safe/semi/full it stays in full the whole time. I'm very confused...HELP

The two fire selector plates are the same size. also I think it may have something to do with the way the safety switch is lining up inside the gun (not inside the gearbox) but I cant see that. Is there something I'm supposed to do to make sure the gun is lined up properly before putting the gear box back in?

There's a little spring that sits on the cut-off lever arm (sticks out of the mechbox on the left side). the spring sits on a post on the selector plate and pushes the cut off arm forward.

Make sure the spring is there....make sure the spring is moving the arm freely (i.e. not getting stuck).

If that's all good then the notch of the selector plate is probably moving the cutoff lever arm back prematurely (it's only supposed to move it when in Full). You can either try to nip a bit out of the selector plate with a sharp exacto knife...or buy and try a different brand of selector plate.

There's other things that can happen...but that's probably the most probable thing.

Best of luck,

Tys

I'd check spring too, otherwise the cut-off won't make it shoot semi.

I see what your saying and everything checks out but the gun wont even go to safe which is on the exact opposite side. It seems as if the selector plate isnt moving at all. It moves outside of the body.

If the selector won't move the plate once it's in the body then don't force it (you'll break the selector/selector disk that way).

If the selector plate is binding in the body then switch selector plates or shave/file (the selector plate not the body) where it's hitting. Some mechbox shell/plate/body combos result in too tight of a fit.

I Just dont understand how it's too tight. because I was having the same problem with the selector plate that came with my gun before it broke. I reassembled everything the way it came out and something wasnt working. then it snapped.

Alright I fixed that problem but it seems as if the trigger safety isnt working now. as if the Selector plate isnt moving far enough forward to engage it.