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JG / CYMA 8mm Reinforced Gearbox for M4 M16 Series Airsoft AEG with Mosfet - Front Wired
[GB-M4-MOS8mm-F]
$70.00
by Ryan G. Date Added: Saturday 12 November, 2011
This is a good quality, high value mechbox for the price. Out of the box it was shooting 430fps with a standard 363mm barrel and m4 hopup. I swapped the spring with a M120 and it shot 398fps on avg, perfect for outdoor use as most of my fields cap full auto at 400fps.

Upon disassembly, the interior of the box seemed well lubricated - not full of the vaseline type grease seen in some other JG AEGs. I regreased and reshimmed the box before using but coming straight out of the box it looked fine - shimming could have been a bit tighter for lipo use but that is nitpicking. The piston head, cylinder, cylinder head and air nozzle form a tight airseal. Wiring is a decent gauge and can handle the load of a 11.1v lipo no problem.

Mosfet works well, trigger response is excellent with a 11.1v 1300mah PEQ lipo battery. ROF is exceptional, a quick tap of the trigger on auto will give you a double tap. The Mosfet chip is slim ehough to fit under a standard M4 RAS handguard (electrical taped to barrel to keep steady and water resistant) - just run the plug up to a PEQ box.

One potential issue: The control wire for the mosfet chip is very thin and the solder point rather fragile. When installing the wiring be gentle and DO NOT apply pressure/pull to the wiring harness - this applies to when you split the M4 receiver as well. Make sure to give yourself adequate slack.

Rating: 4 of 5 Stars! [4 of 5 Stars!]
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