Beta C-Mags

[HorseSoldier]

I wonder how well they worked. If it was a successful idea, I'd think that someone would have made them for the civilian AR market at some point, but the only AK/AR hybrid mags I've seen there were specifically for 7.62x39 caliber ARs (a design with some fairly notorious reliability issues, but as I understand it that is more about trying to get the geometry of 7.62x39 rounds through the AR-15 magwell than the magazines themselves).