BOOM! That's what happens when you load 164 pounds of Tannerite, the aluminum and ammonium nitrate explosive used in exploding targets, inside a barn you want leveled. Fire at the Tannerite with a rifle, and take cover—bye bye, barn.
No, I have no idea why the on-camera guy is wearing a Nixon mask. Probably to avoid being arrested for what I'm assuming are about three dozen laws he's breaking. This isn't some secluded field miles from anywhere; you can hear cars passing by on the road right before the explosion.