Carlson's Buckshot choke tube is designed to give you tight patterns downrange with 00 & 000 buckshot. It features a constriction designed specifically to optimize patterns with large and small loads alike and will extended about 1" out of the barrel. Machined out of 17-4 heat treated material this choke can be used with Lead, Steel, and Hevi-Shot loads. NOTE: This choke cannot be used with any Steel Shot larger than BB or with any Steel shot faster than 1550 FPS.