[El Gato]

I wonder how many pounds of C4 and ballbearings it would take to detroy a bus.

One or two pounds would do the job. A bit more if you are setting it off from under the bus, rather than inside, and assuming your object is to kill the passengers, not shred the engine and transmission.

Consider that a Claymore mine only weighs about 3.5 pounds and much of that weight is the "ball bearings" (about 700 of them) and the plastic case.

[BobS]

"A bit more if you are setting it off from under the bus, rather than inside, and assuming your object is to kill the passengers"

I suggest only 8 ounces in the middle of the bus. The compression wave will kill people within 30 feet.

This is a good discussion to have. The terrorists know this and have studied it. It's about time average Americans become aware of this stuff and keep their eyes open and take the headphones off.