AC6000 BT ChronographDescription AC6000 BT is a professionally made chronograph designed by Acetech airguns and airsoft replicas. Manufactured with high quality materials and components, AC6000 BT smoothly and accurately measures velocity, kinetic energy, and rate of fire. The measurement range of a single shot is between 30 to 400 m s, whereas a burst is between 100 to 5000 rounds per minute. The 36mm wide speed measuring tube is broad enough to accept most barrels and