Carlson�s TSS Turkey Winchester .640 12ga Choke Tubes are optimized for federal premium heavyweight tss turkey loads but also work exceptionally 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. combining this with the ability to carry energy further makes them ideal for 12 and 20 ga. Tungsten super shot (tss) has a 22 percent heavier density than heavyweight shot and a 56 percent heavier density than traditional lead shot. It puts the maximum amount of pellets possible in a 10 inch circle at 40 yds. the 12- and 20-ga. Shells will include the flitecontrol flex wad that gives hunters the ability to shoot any choke tube they prefer. Long-range turkeys don�t stand a chance.