It uses a rotary bolt with a spring loaded ejector and an extractor facing down, ejecting spent shell casings downward, allowing easy ambidextrous use.

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.

[6] While other bullpup rifles (FN 2000, Kel-Tec RFB, Desert Tech MDR) have used forward-ejection to allow ambidextrous use, these solutions tend to add parts and complexity to the design.

[4] The Kel-Tec M43 is a similar design replacing polymer parts with parkerized steel or with wood for the stock furniture.

Compared to RDB models, it has additional integral folding sights and a heat shield over the short stroke piston.