Guys, I'd like to mount a shotcam onto my AR-15 (top rifle depicted below). This AR has the typical old fashioned forearm grips and thus can't be used to mount anything on it. Other than a bayonet lug rail, which my rifle does not have, is there something that'll clamp onto the barrel without interfering with use or accuracy? I Like Magpul but I looked around and didn't see anything on the net I could use.