Watch a 20mm anti-tank rifle destroying an Apple iMac in slow motionJesus Diaz5/12/14 7:38pm361EditPromoteGo to permalink RatedRR is back again with the big guns. How big? 20mm big! Witness the power of the Lahti L-39, a Finnish 20mm anti-tank rifle used during World War II. So powerful and accurate that they even took down airplanes with its fully automatic variant. Here you can see it destroy an Apple iMac.