New Gearbox Compatibility (or not)

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New Gearbox Compatibility (or not)

Post by turtlewoo » Mon Mar 21, 2016 9:09 pm

Hi everyone. Been awhile.

So, as not to bore you with the details as to why I am doing this, I'll just get right into it and say that I am trying to replace a G&G Gearbox with a Matrix one in a Combat Machine M4... I have a bit of maintenance experience, but this is way harder than I thought it would be, as I assumed "compatible" meant you could just drop it in and go. Apparently I was wrong. I had to spend weeks slowly removing material from the back of the lower receiver so that the rear pinhole would line up, only to find out that now the front hole on the box is sitting too far back, so I had to cut new ones into the front lower receiver pinholes. Only to find out that the mag-release is sitting too far back too. And NOW, when I try to put the two receivers together, the front part of the shell of the mechbox (around cylinder head nozzle thing) is hitting the rear of the hopup unit so that I cant get that pin to line up either. Needless to say, its been a real headache.

My idea as of right now is to cut down the back of the hopup unit (where I can) until the gearbox can move forward enough for me to put the two receivers together. I realize that I also may have to cut down the cylinder head nozzle so that the bb's don't land too far forward.

I'm doing my best to think of any unforeseen issues that might come with this route. Can anyone think of anything or any alternatives? Short of setting the whole thing on fire? Maybe there would be some feeding issues?

Thanks in advance for the wealth of knowledge that I know is on these boards.
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Re: New Gearbox Compatibility (or not)

Post by Guges Mk3 » Thu Mar 24, 2016 7:31 am

Stop cutting and just get a new G&G mechbox.

You have ruined a receiver now for pretty much trying to seat anything stably now...if you start cutting the hop-up do you think your mags will fit and feed?

AEG"s are a system..."minor" modifications are okay. Major modifications is not recommended.
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Re: New Gearbox Compatibility (or not)

Post by Tank » Fri Apr 08, 2016 5:57 pm

There's no reason a standard V2 gearbox should NOT fit without having to perform major surgery. Sometimes there are minor fit issues related to selector switch &/or mag catch but nothing that would require anything near what you've done. Unless you're converting a two-piece hop-up to a one-piece, that requires some fairly significant modification.

As Guges said, you pretty much destroyed your existing lower. You're going to have to get a new receiver set.
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