Browsing the Kel-Tec website I came across the SU-16C piston-driven AR. Bud's Gunshop lists this rifle for $510. It weighs 4.71 lbs empty. Does anyone have experience with this rifle? Whaddaya think of it?
http://www.kel-tec-cnc.com/su16c.htm
http://www.kel-tec-cnc.com/su16c.htm