I bought this for my CMMG Banshee AR-22. The magazine fits into my lower receiver perfectly and this is actually my favorite magazine to use (I've only owned two AR mags) because the lip on top gives a place for my hand to grip the mag and that lip on my magazine fits flush with my lower receiver. It's genius. I love the design of the magazine but I'm sure if I took it out into the woods I'd probably catch a lot of dirt and debris inside those designs.