A Possible Kassam Response

Phalanx Close-In Weapons System (CWIS) fires 4,500 rounds per minute, cuts down mortar rounds out of the sky.

The MK 15 Phalanx Close-In Weapons System (CIWS - pronounced "sea-whiz") is a fast-reaction, rapid-fire 20-millimeter gun system that provides US Navy ships with a terminal defense against anti-ship missiles that have penetrated other fleet defenses. Designed to engage anti-ship cruise missiles and fixed-wing aircraft at short range, Phalanx automatically engages functions usually performed by separate, independent systems such as search, detection, threat evaluation, acquisition, track, firing, target destruction, kill assessment and cease fire.

Phalanx underwent operational tests and evaluation onboard USS Bigelow in 1977, and exceeded maintenance and reliability specifications. Phalanx production started in 1978 with orders for 23 USN and 14 Foreign Military Sales (FMS) systems.

Phalanx is a point-defense, total-weapon system consisting of two 20mm gun mounts that provide a terminal defense against incoming air targets. CIWS, without assistance from other shipboard systems, will automatically engage incoming anti-ship missiles and high-speed, low-level aircraft that have penetrated the ship primary defense envelope. As a unitized system, CIWS automatically performs search, detecting, tracking, threat evaluation, firing, and kill assessments of targets while providing for manual override.

Each gun mount houses a fire control assembly and a gun subsystem. The fire control assembly is composed of a search radar for surveillance and detection of hostile targets and a track radar for aiming the gun while tracking a target. The unique closed-loop fire control system that tracks both the incoming target and the stream of outgoing projectiles gives CIWS the capability to correct its aim to hit fast-moving targets, including ASMs.

The gun subsystem employs a gatling gun consisting of a rotating cluster of six barrels. The gatling gun fires a 20mm subcaliber sabot projectile using a heavy-metal (either tungsten or depleted uranium) 15mm penetrator surrounded by a plastic sabot and a light-weight metal pusher. The gatling gun fires 20mm ammunition at either 3,000 or 4,500 rounds-per-minute with a burst length of continuous, 60, or 100 rounds.

And here's the clip.