it's great.. sturdy (no 'pot metal') & able to stand a nuclear holocaust.
Well... almost, the feed tip is fragile (I advise you don't let the spring go, as it will send the tip flying, in some random direction(s)
& then the cap on the bottom... it's not sturdy plastic, one decent drop will shatter this thing, it's also to loose in a holster (it got lost in my Crossdraw Tac. vest) electrical tape (if you want to keep color continuity) will remedy this issue, but good ol' duct tape is the best.
I don't know if I got extremely unlucky (I'm somewhat infamous for that among my team mates)... but three of the five I ordered began leaking within a month
& unfortunately I'm only able ti give them a 3/5 because of this
sturdy, strong metal
I personally am getting close to 100 shots a cartridge (good gas management)
Work great while they last (the two of mine that still hold air, are running strong, over a year later), the other two only get about ~10 shots a cartridge
Slightly increase FPS, over green gas
three of the five I ordered began leaking within a month.
(possible con... but I find it a pro/neutral) they are a bit heavier than most mag's out there