Made from 17-4 heat treated stainless steel these chokes are for the Winchester Mossberg 500 Browning invector Weatherby and Savage 12 gauge & 20 gauge shotguns. - Steel Lead & Hevi-Shot may be used in all constrictions with the exceptions listed below. - No Steel shot larger than #BB or speeds exceeding 1550 fps should be used in choke tubes tighter than full. - No Steel Shot Larger than #4 may be used in our Turkey Choke Tubes - These choke tubes are backed by Carlson's Lifetime Warranty and Made in the USA!