I have six of these and they're great. WE mags have a horrible tendency to leak so what I recommend is that in the order comments, you ask that they test for leaks. They actually do read all of those and I've never had an issue. In store they check for me and it's great. Now with my time with these mags, they have yet to fail me, but I have some advice for when you want to keep them working. ALWAYS, and I mean ALWAYS keep some gas in them. I don't mean full all the time, but some gas will keep all the seals intact. Also, what I've noticed is that the paint on one of mine is really scratched up because I shoved it as hard as I could back into my mag pouch without looking. Honestly though, with the quality of the metal on these mags, and a little maintenance, these mags work great. Cool down isn't too bad either. It definitely can't compare to KWA's performance, but on full fill, it will last the whole mag in almost any weather. On fully automatic, the gas and performance might be hindered by cool down but I don't know of many situations where you will be dumping entire magazines in cold weather.
Full Metal Construction
Reliability (If properly maintained)
Dry Fire option
Holds plenty of gas
Requires maintenance to work
Probably the cheapest gas blow back rifle magazines around
When you're carrying a bunch, it gets really heavy
(I carry six and my vest is now 20 pounds)
Overall, very good product.
Rating: [5 of 5 Stars!]