ballistic silvertips are Winchster's name for a Nosler ballistic tip. They're more for long-range ballistics and rapid opening against light targets at lower velocities associated with longer ranges. Use one on something heavy or at higher velocities, and they'll come apart.
There in your statement comes the "Magical" properties of the Ballistic Silvertip. When used on a whitetail at 100 yards with a .308 or 30-06 they blow apart on impact and cause a massive exit wound about the size of a softball.Dead deer with messy, nasty wound looks "bad arse" so it must be a great bullet.
They are absolutely a along range, low velocity expansion bullet.
I have used them with great success on Hogs out of my .308. Leaves a nice exit wound that leaves a good blood trail when standard bullets would not penetrate the neck/chest shield on the exit side which leaves no open wound for blood to leave a trail.