I got one: Original piston drive 5.56mm Armalite AR-180 (Sterling)

[jmoore]

I sold my Costa Mesa in mid 2010 for ~US$1100. And that was after I had "ruined" it by making it work w/ M16 mags (except the plastic Magpuls etc.) The mag release still pivoted, but it pushed a custom spring loaded "L" that engaged the '16 mag's catch hole. Also had to make a form block to massage the relief area on the left side of the lower receiver.