The RDB was designed to be modular, and is broken down into four Assembly Groups, held together with
HK style pushpins: • The Barrel Assembly Group, made up of the barrel assembly,
optic rail, handguard, gas system and charging handle; • The Receiver Assembly Group, primarily the serialized steel receiver, butt pad, recoil buffer and heat shield / cheek rest; • The Bolt Assembly Group, consisting of the bolt carrier, guide rod, recoil spring and bolt assembly and; • The Grip Assembly Group, containing the fire controls, trigger and hammer mechanism, magazine well and ejection port. The RDB operates using the
short-stroke piston system, firing from a
closed bolt. A gas regulator is built into the Barrel Assembly Group to allow the operator to adjust the amount of gas used to cycle the action. The RDB uses a unique downward ejection method to permit the operator to fire the rifle from either side. During the extraction and ejection cycle, spent casings are dragged rearward over the magazine to the ejection chute located directly behind. The RDB bolt uses dual ejectors to assist in positive ejection, and has been demonstrated to operate normally even if the rifle is turned upside-down. While other bullpup rifles (
FN 2000,
KelTec RFB, Desert Tech MDR) have used forward-ejection to allow ambidextrous use, these solutions tend to add parts and complexity to the design. Other bullpups can be converted to eject from one side to the other (
IWI Tavor,
Steyr AUG) but may not be able to do so without special parts. ==Variants==