[cynwoody]

If a bunker buster was to hit a 2 or three floor building or a home, it would blow up after penetrating the first cavity it finds, unfortunately, that would be the next level down.

I seem to recall an explanation that bunker busters count the successive shocks as they penetrate floors and can be programmed to detonate after a set number of floors or after coming to rest, whichever happens first.

[MJY1288]

That makes sense as well, in other words.... It's not much different then how a Tri-Burst select-fire trigger works on a M-16......... a ratcheting trigger