Carlsons Replacement Choke Tubes. Manufactured from 17-4 heat treated stainless steel. These chokes may be used with lead shot on all constrictions. (Steel shot larger than #BB should not be used in any choke tighter than full). Winchester 12ga Improved Cylinder Flush Mount Choke Tube.
Constriction-Improved Cylinder, Diameter is .720 Carlsons item #122112