I've been testing the new Kel-Tec RDB for a few weeks now and have put over 1,000 rounds through it. The RDB stands for "Rifle Downward-Eject Bullpup" and it's truly unique in design. The RDB is chambered for 5.56mm and Kel-Tec has been working on it for a couple of years. Get ready, the RDB is about to hit shelves soon.
Copper Custom: http://www.coppercustom.com/
Challenge Target: http://www.challengetargets.com/