Jing Gong just released their latest M4A1 AEG, now with “Metal Body”. The new AEG features a hardened gearbox housing and one piece metal barrel equipped with voltage stablizer electronic board. : RSOV.com

Jing Gong’s M4A1 was the best M4 AEG availabe at the time of its release late last year, and in some aspects it still is today. I’ve tried having mine as close to stock as possible for the last nine months and I am very satisfied for the cheap, cheap price I paid. Why no upgrades? Because it defeats the purpose of buying a cheap China-made gun, and low FPS means I can get up close and personal. *mwahaha*

Performance

As discussed in several other reviews, this rifle already shoots 360-380 FPS, the spring having around the same power of an SP110. Mine still shoots 360 +/-4 fps; pretty consistent considering the stock airseal nozzle doesn’t have an o-ring and the inner barrel isn’t tight-bore yet.

The plastic bushings are still holding up, so no need to replace them with metal ones yet. I think the plastic bushings also contribute to its fast rate-of-fire even on 8.4v mini-batteries due to less metal-on-metal friction, and if the shimming is too tight then the plastic just gives way.

Speaking of the batteries, the stock 8.4v 1100mah battery is a wonder. A full charge lasts at least 1,200 rounds. It still works fine, any other NiMh or LiPoly battery would’ve degraded by now. It’s charged using a BOL-01 instead of the included wall charger, mainly for the convenience of automatic cut-off, so I wouldn’t know how the stock charger performs.
Misfeeds

There was only one time when I needed to open up the gearbox, and it turns out there was no need to in the first place. I had misfeeds using both the stock hicap mag and G&P mags. I installed a sector chip but the misfeeding problems persist, until I put silicon oil into the magazine tubes. So don’t put a sector chip until after you’ve thoroughly checked your magazines.
Durability

The paint is easily stripped, it doesn’t even chip off, it just disappears. This might be good if you want the distressed look or planning to paint it anyway. The plastic handguard was damaged by a high-powered gun, which had no business in a low-power CQB site by the way. Other than that, everything is still fine: the plastic receiver’s “ears” are still intact and the outer barrel is still straight… even after I tripped on it.
Good buy or Good bye?

I’d still recommend the M4A1 due to the points I’ve mentioned:

* Great out-of-the-box performance
* Decent FPS
* Impressive rate-of-fire
* Even more impressive battery performance and runtime
* Considerably tough, even the plastic receiver

Comparing this to the recent releases of M4s offered by other ACM manufacturers, the only real shortcoming is its two-piece outer barrel. Other M4s already have one-piece barrels eliminating the barrel wobble and allowing the use of a sling attached to the front. Other than that, the JG M4 and its relatives are still very good buys.