[xkqd]

My money is on the breaching charges that these high speed folks use. Particularly in conjunction with the thousands and thousands of reps that folks put in practicing breaching. It's enough force to rip a reinforced door clean off the frame. Grenades are a close second but I don't think they train into the thousands with actual field grenades.

Maybe an instructor sure, but we're talking about SF here.

I don't doubt that artillery will also do this kind of damage, so I'd be curious about what the brains of field artillery folks look like.