R2D2's demented big brother, the iconic 20mm cannon shell squirting Mark 15 Phalanx close-in weapons system (CIWS), remains the last line of defense for many of America’s most capable surface combatants. The video below shows a AV-8B Harrier making a high-speed attack run on the USS Germantown while its Phalanx, which is empty, attempts to blast it out of the sky.
If the Phalanx had a full load of 20mm, that Harrier would have been hosed. Also of note, it looks like it stopped its attack so as not to blast the top of the Germantown’s mast off. That and a seven-second long string of 20mm was likely plenty to shatter the target considering the M61 Vulcan cannon rips through ammo at up to 6,000 rounds per minute.