G&P Mechbox/Internals quality

[delta76]

I'm currently putting together a custom build M4A1 (front wired), and I've been looking for a complete drop-in mechbox. I've limited by budget to $200 for the mechbox because at the moment I've gone over my head on externals.

I've been looking at the G&P M120 8mm complete gearbox that Jugglez retails for $199. In a perfect world I'd probably go with a Systema, but I thought I'd look into this first. I've been trying to find reviews/info on the quality of this gearbox and so far I've only been able to find one thread, and it wasn't pretty (shattered gears after a few thousand rounds; and I wasn't too impressed with the quality of the internals). I'm not sure what setup the gearbox was run on, but I remember reading something about a lipo being used.

My questions are: (note I've tried to answer them myself but haven't found anything definitive)

Is this mechbox lipo-ready?
If I run it with a lighter spring what would the effect be?
Are internal failures common with G&P?
I'm pretty anal about airseal so I'll probably end up swapping out the cylinder head, piston head, and nozzle; are systema components markedly better in terms of airseal?

Are there any other complete, drop-in mechbox options in this price range that may perform better, or should I suck it up and go with a Systema?

[Amos]

G&P mechboxes are excellent starting places for upgrades.

BUT, before you take a shot with it get an experienced guntech to open it up and shim everything properly.

G&P gets pretty awesome air seal... but if you're so anal about it and want it to be PERFECT get an modify cylinder set 9/10 that I've installed have perfect aireasl even with the nozzle on the cylinder head.

Systema parts are out dated in my opinion, they've started to move away from the general airsoft market and focus more on the military/law enforcement training market.

Right now Prometheus is top dog... but the price also reflects that, Modify is a close second

[delta76]

I live for Modify cylinder sets, I've installed them in everything I have and tout them to everyone I know. The idea of considering the Systema was that it was only 60-80 dollars more, which I can see myself spending to bring the G&P up to snuff. The idea that the Systema product may not be all it's cracked up to be is news to me. Thanks for the input.

For what it's worth, I wouldn't run a lipo setup for anything other than the convenience of a buffer tube battery. I'll stick to what's worked for me with NIMH 9.6V. I prefer a milsim rig and emptying a mag in 4 seconds does nothing for me. I would probably run an M110 spring so I'm not sure if the extra reinforcement and 8mm bearings/bushings are really necessary.

[CDN_Stalker]

While you have the mechbox open, get rid of the tappet plate, they mostly snap within the first thousand or two rounds.

And go Modify as much as possible.

[lemegacool]

the stock spur gear in mine was crooked, making shimming impossible... replaced that with a set of helicel gears!

true for the airseal thought... its awesome!