Action: Semi Auto - Caliber: 5.56 - Barrel Length: 20 - Weight: 7 lb - Through an ingenious and simple arrangement we have solved the main disadvantage of Bullpup rifles; case ejection. Traditional side ejection is not ambidextrous and forward eject like in the FN 2000 or the Kel-Tec RFB is quite complex. - The RDB (Rifle Downward-eject Bullpup) features a rotary bolt with a spring loaded ejector and an extractor facing down. The spent case is pulled backwards along the top of the magazine and then ejected through a vertical chute. The hammer is U-shaped and runs outside the chute and above the magazine. Obviously the bolt travel is longer than traditional designs but well within the ergonomic constraints of a rifle. Other advantages are gravity assisted ejection higher bolt energy at feeding and a slower full auto rate (when applicable). - The RDB is built around a common steel skeleton formed by the receiver and barrel sub-assemblies. Bolt bolt carrier firing mechanism ejector chute and bolt stop are identical for all variations. The short stroke gas operated piston is fully adjustable for different ammunitions and muzzle attachments.