2 completely different animals. The Differences roughly are you can use the BST for up to medium game but in 30 cal and up 180 grains it is good on heavier game. The partition is good on medium thru very large game. The partition tends to retain more weight after penetrating but usually no better then 60% and has killed more animals reliably then probably any other big game premium bullet. Go to www.nosler.com and they will show a sectioned example of their bullet types.