Browning Diamond Grade Choke Tubes are for use with back-bored barrels and feature perfect concentricity for superior patterns in Browning shotguns. Choke tubes are a necessity if you are a seasoned shooter or just getting started, along with other supportive shooting gear such as bags, hearing protection and shooting glasses. These Browning weapon accessories can make a difference in your weapon. If you want to achieve superior patterns, use a Browning Diamond Shotgun Choke Tube. – Longer choke taper inside Invector-Plus choke tubes for use with back-bored barrels;