This might be a retarded question but why aren't there any windowed aluminum/steel mags? By which I mean not just a hole in the side but an actual window or something else so you can tell how many you've got left. I've only ever seen this in plastic mags. Am I blind? I'd buy em if they existed. I LIKE being able to just look and SEE how many rounds are loaded but I'm racist against plastic. Pic unrelated.