Long Invector Features Lead shot Steel Shot Copperplated Shot Nickel Shot Hevi-Shotshells and Buck Shot can be used in our Sporting Clay Choke Tubes. Steel shot larger than BB should not be used in any Sporting Clays Choke Tube tighter than Full Constriction. Our Sporting Clays Choke Tubes will throw tighter/denser patterns than Flush Mount Choke Tubes due to a longer parallel section. Long Invector Specifications Carlson's Long Invector 1.9-inch Flush Sporting Clays Choke Tube .401 Sporting Clay Modified