Antiaircraft guns (also known as “flak guns ... arsenal of the AC-130 Spectre gunship. Meanwhile, the 20mm Oerlikon still arms some naval units, nominally as a last-recourse anti-air weapon ...

It is used in a variety of rotor wing aircraft in the “door gunner” position and is used by the U.S. Navy for its riverine ... three different guns; .60 caliber, 20mm, and 27mm.

The US Navy equips all its surface combat ships with a powerful gun called the Phalanx. This is what it looks like in action. Produced by Eames Yates, Original Reporting by Jeremy Bender.

Here, a soldier shoots the Cornwall's 20mm close range guns during a night firing exercise. The nuclear-powered HMS Astute is the largest attack submarine the Royal Navy has ever commissioned.