G&G M4 CQB-R Gearbox Info

[xGR1MR33F3Rx]

Hello, I have purchased a G&G M4 CQB-R AEG rifle from Cabela's recently and have had trouble finding out accurate information about the gearbox and what exactly is inside of it in terms of quality of parts, size of spring etc.

This is the rifle: http://www.cabelas.ca/index.cfm?page...=1387&ID=22159

I really like this gun, I've had it out for a few skirmishes and have won all of them XD. But, I would like to know if there are any upgrades to the internals that anyone would suggest for this exact rifle? I have heard people replacing the piston heads on it, but really that's it.

I would also like to know if I could maybe install a stronger spring safely, for a little more fps. The gearbox is made of "reinforced metal" websites say, so I would assume its strong and durable.

In conclusion, I would like to start "Perfecting" my rifle with internal mods before I start to deck it out in accessories. I don't have much experience with disassembling gearboxes in AEGs, but I do have a high aptitude for working with my hands, and understanding mechanical systems (being an Engineering student ). I'm pretty confident I can so some of these gearbox upgrades without screwing up my gun, except for electrical modifications, not keen on those.

Any help or experience with this gun would be much appreciated. Thanks.

[Styrak]

Run it until something breaks. No sense in opening it up when you don't have to.

[Armoredshell]

Best upgrade for this G&G would be a 6.03 (300 mm) barrel, a king arms one piece hopup, and gauder clear rubber. That's all I have done to mine so far and it's a vast improvement over the stock setup