I've gotten to hold Huang's JG Clear M4 GBBR, the upper is metal, and the lower is clear plastic, but not the tinted kind so it definitely needs a painting.
The plastic felt great, really flexible, not brittle at all, I wouldn't really worry about it breaking on me, and for the price, I'd take it over the KJ anyday, but that's because GBBR is just a toy for me at this point, nothing I would commit to financially to make fieldable, just something to play around with, maybe use at CAPS etc.
__________________
|