Carlson's TSS Turkey Choke Tubes are optimized for Federal Premium Heavyweight TSS Turkey Loads but also work well with other manufacturer's turkey ammunition (smaller shot size 7-9). The Federal Premium's Heavyweight TSS Turkey Load has an incredibly high pellet count in both 7 and 9 shot, along with their ability to carry energy further, makes them ideal for .410, 20ga and 12ga.Tungsten Super Shot (TSS) has a 22% heavier density than heavyweight shot and a 56% heavier density than traditional lead shot. It puts the maximum amount of pellets possible in a 10" circle at 40 yds. The Heavyweight TSS shells will include the FliteControl Flex wad that gives hunters the ability to shoot any choke tube they prefer. *No steel shot larger than #4 may be used in our Turkey Choke Tubes, 410 shotguns only.