Old/New
Guess the .410/210s would fit that bill?
Maybe not... I have tried them in my Knight 45's with a Harvester Crush Rib sabot. i can get them down, but I also see that I distorting the sabot all to heck as it squeezes it's way though the crown of the bore.
Because of the difficulty loading the the 41/210's I decided to try some 40/180 Gold Dots - now those work get - fly great and hit very hard.