Introducing Carlson's innovative new Bismuth bone buster Choke Tubes, meticulously engineered to deliver peak performance with Bismuth ammunition. These tubes are crafted with precision CNC machining from 17-4 heat treated stainless steel, featuring an extended parallel section inside the Choke that outperforms standard factory alternatives. After undergoing rigorous testing with a wide range of loads, these chokes ensure exceptional patterns when paired with Bismuth ammunition, resulting in devastating performance. Available in both mid range (with a .025 constriction) and extended range (with a .040 constriction), these versatile chokes accommodate both lead and Hevi-Shot loads. The mid range model is compatible with all steel shot types, while the extended range version supports steel shots up to size #2. Elevate your shooting experience with the unmatched dense patterns delivered by these state of the art Bismuth Choke Tubes, all backed by Carlson's unwavering lifetime Warranty.