Can anyone explain the technial differeces between the BT, Patitions and the nwer Accubond?
Does it replace either of its predecessors?

Nosler says that they are replacing the BT with the AB. Basically, the AB is a bonded version of the BT. The Partition is a different animal with similar results on game to the AB. The Partition works not by bonding the jacket to the core, but by using a partition in the middle of the bullet to limit weight loss, thus increasing penetration.

also the partitions have a lower BC so arnt as good for long range.

They are a little lower that the premium bullets
but not that much lower. Nosler partitions are excellant for big game.