A few months back I had the pleasure of running one of the new Century Arms C308 battle rifles through a 1,000-round torture test. While loading the magazines and firing all the ammo was positively brutal, one aspect was surprisingly easy - finding affordable magazines.
Good thing too, since most surplus G3 magazines hold 20 rounds. If you just did the math, you know I had to buy 50 magazines for the test. At face value, if someone were to say they bought 50 HK magazines of any variety, most shooters would assume that person had either hit the lottery, or had a rich uncle pass away. Let's face it, HK products aren't known for their affordability. They are however, known for being nigh-indestructible and relentlessly reliable.
The HK G3's magazines still retain that legendary reliability, but without the bank-breaking cost. There are actually two main varieties of surplus German G3 magazines available on the market today. Semi-glossy black aluminum 20-rounders, and matte dark grey steel versions of the same capacity.
Both are dimensionally identical, but the aluminum ones are predictably much lighter than the steel variety - they're also a bit more expensive. But like so many other things in the industry, you get what you pay for. In my experience with G3-pattern firearms, the Aluminum magazines tend to insert easier than steel ones, but they do have one small shortcoming; tensile strength.
The steel pattern magazines are so overbuilt, they would be used as stepping stools or makeshift hammers. The aluminum ones, while durable, wouldn't tolerate this sort of abuse nearly as well - at least when empty. Once full of large, heavy .308 ammunition, the magazines resist crushing much better.
I digress, these magazines are influenced by previous Mauser Werke designs, like the STG-44 it originated from decades before. As such, the magazines don't insert straight into the magazine well like an AR-15, but rather rock into place like an AK47 magazine. This lockup is so strong, it's next to impossible to forcefully dislodge one without utterly destroying it.
One of the cooler things about the design, are the reinforcement ribs that run along the magazine body. They give the G3 magazines a very unique appearance, while adding strength to the relatively thin aluminum walls.
So, how do these magazines hold up compared to more modern designs? Well, they can't take the same amount of punishment as modern polymer magazines like the ubiquitous Magpul PMAGs, but they aren't as fragile as the aluminum 3-round 5.56mm HK93 either. While not as robust as their steel brethren, these magazines offer shooters a lighter weight option that looks as good as it runs. Just be careful buying used ones - sometimes these magazines get slightled deformed by previous users. The good news is that it's pretty easy to bend them back with a screwdriver. Though at their current price, it might simply be easier to buy a new one.