Maker: Easy Company (?)
Model: ?
Item weight: ?
Calibre: 6mm BBs
Magazine capacity: hi-cap 300 (?) rounds
Price: ? yen
Manufacturer: Master Molder
Calibre: 5.56x45mm
Magazine capacity: 30 rounds
I don't own very many M16 hi-cap magazines. The only ones I have came with airsoft models I've bought, in this case a Classic Army M15A4 Rifle and CA249 MKII. I've relied on my First Factory 5000 round box mag until recently, when I had the idea to own some normal M16 magazines. But carrying a lot of magazines is heavy; I know, I used to carry a dozen or more G&P standard mags. And most of that weight is just metal casing, the plastic internals and the BBs themselves do not weight a whole lot. While my AEG would undoubtedly be lighter by loading it with a 300 round hi-cap, my deuce gear would be much heavier, and that's what wears you out. Thus, I was in search of a good plastic alternative. Plastic mags have a few advantages: they're lighter, when empty they rattle not as loudly, and they don't chip paint. Of course durability isn't as strong, but magazines are not commonly broken items in my experience.
The most obvious plastic M16 mag is the thermold. From what I can gather (information borrowed from Troy's Magazine FAQ), they were developed by Master Molder in Wilson, South Carolina. They were a possible replacement to the aluminum magazines being used at the time by the US military, but an agreement was never reached. The USA thermolds were made of from DuPont Zytel, a fiberglass-impregnated plastic that is both strong and has a high melting point. Master Molder licensed the design to the Canadian military, who manufactured the design using a less expensive plastic as a substitute for the DuPont Zytel, which resulted in the plastic mags melting during sustained fire. They could also crack in cold temperatures if dropped or otherwise hit hard enough. This history of the thermold matters naught for airsoft, but there is a common misconception that all thermold magazines are junk, and clearly that is not the case, as the American-produced ones are very reliable. Master Molder also produced 20 round style thermolds which are apparently the best aftermarket 20 round M16 mags available.
Anyway, I searched around and found some States-side retailers selling thermold magazines. I found three basic brands: a company called "Stealth", Easy Company, and STAR. I know G&G makes a 450 round thermold hi-cap, but I've heard less than stellar opinions of their magazines. STAR are the most expensive, with a MSRP of $35. I found Easy Company's thermold selling for $30. The "Stealth" thermold was $26.99 at Airsoft Atlanta. Airsoft Atlanta had some other things I was looking for, so I bought four of the "Stealth" mags from there.
Now for some investigation. These "Stealth" brand mags came in packaging labelled "TSDtactical" on the front, with what I think is a model number of "MSDERMIL42TC". On the back of the cardboard backing is a link to AirsoftSD. Now I thought this may have been the "Stealth" company brand, but it appears SD is merely Specialized Distribution; an importer, not a manufacturer. I looked around everywhere, but found nothing on the company "Stealth". Then I searched WarGameClub for thermolds, and found two thermolds produced by Easy Company, one black and the other a translucent smoke color. The latter was identical to the mags I had bought at Airsoft Atlanta, and searching around for more photos, every detail I could make out seemed to show that my "Stealth" mag was actually a product of Easy Company, or at least a good copy. The most common Easy Company thermold is the black version, but WGC sells the semi-transparent version as well, so it does exist. I believe Specialized Distribution imports the Easy Company mags for TSDtactical. For the purposes of this review, I'm going to ASSUME the magazines I bought at Airsoft Atlanta are actually the Easy Company brand and not this "Stealth" brand they advertise them as. I trust the above evidence leads to this conclusion. If I am wrong, then take this as a review of an Easy Company "Powermag" (as is on the EC packaging, in big letters) M16 thermold mag clone, and that the actual thing may perform better.
The magazine is a translucent smoke color, so you can clearly see the BBs inside of it. This isn't quite as useful as G36 or SIG mags, as more than one-third of the mag is inserted into the magwell (the top half of the mag is BB capacity, the bottom half are the internal workings to get the BBs to feed), so while you can tell when you're getting close to empty, you won't be able to tell if you're mostly or even half full unless you take the mag out and visually inspect it. The plastic itself seems strong and will stand up to some rough treatment, but I wouldn't hit it with a hammer (nor should anything in airsoft). There isn't much flex in the body, which has a nice textured feel to the wide left and right sides, but the thinner front and back sides are smooth. The loading sliding door takes some force to open, but it may just take some breaking in. It's probably a good thing as you don't want it opening by accident. The bottom of the mag has a single Phillips screw holding it on (it slides forward to remove), and the winding wheel is indented into the mag some, so it does not stick out past the bottom of the mag, but there is a nice bevel beside it which makes winding very easy. The whole magazine itself weighs about half (ballpark estimate) a Classic Army M16 magazine when loaded with 0.25g BBs. On a side note, you can supposedly get Magpuls on a thermold mag, but they really take some stretching to get them on. Given the shape and texture of the thermold, you can do without.
What are the negatives? It is a plastic nothing like the real thing, and plastic is not as strong as even cheap metal commonly used in airsoft. They are also significantly thicker than normal M16 mags, turning triple mag pouches into doubles, and doubles into singles. Bear that in mind, but any good [non-modular] rig should be able to hold at least a dozen magazines, thus you can carry eight of these thermolds (2400 rounds), which should be enough for anybody. And they're indicative of Canada, which may be a negative for some people.
I used the magazines in my Hurricane HKM4D receiver, which has installed a Systema hop-up and bucking, and I'm feeding them Airsoft Elite 0.25 gram BBs. Didn't give me a bit of trouble during a recent game, which is all you can ask for in a magazine. In testing the spring, I wound the magazine as fast as I could, and came up with a time of about 32 seconds. I did the same with a Classic Army M16 magazine and got about the same time. Releasing the spring tension by way of the BB nozzle latch, the thermold seemed a bit faster and louder than the Classic Army M16 magazine, but that's hardly scientific.
I've only field tested the magazines for one day's worth of play, but I didn't have a single issue in that time. There was one stoppage, but it fixed itself by simply winding the mag up a little. They don't seem to require a lot of winding, but I've been using my 5000 round box mag for so long I have no semblance of an idea of what 'a lot' of winding is. They performed well and have the qualities I was looking for, so I recommend them to myself at least. If you want a loadout of thermold magazines, a decent plastic hi-cap magazine or just something different, then these may not a bad idea. They're not amazing (whatever that would be for a magazine), but they are reliable based on my experience thus far.