Navy Tests New Rounds for Marine Corps Fire Support

Last week the United States Navy successfully tested two new, advanced gun projectiles at its Wallops Island, Virginia, test range. On January 9, 2002, the Autonomous Naval Support Round (ANSR) was successfully fired out to a range of slightly more than 51 nautical miles (about 59 statute miles or 95 kilometers). On January 11, 2002, a second advanced projectile, the Barrage Round, was fired to a range of 40 nautical miles (about 46 statute miles or 74 kilometers). (By way of comparison, existing 5" high explosive rounds achieve ranges of just 13 nau-tical miles.) Both ANSR and the Barrage Round were fired from a standard Navy 5"/54 caliber gun and reached their maximum ranges in less than three minutes.

Naval gunfire is one of the most important sources of fire support for Marines conducting amphibious operations. The 5" gun is the standard fire support weapon carried by United States Navy cruisers and destroyers. A cruiser can carry as many as 600 ANSR or 1200 Barrage Rounds in its magazines. Fully compatible with existing auto-matic loading systems, they can be fired less than 90 seconds after a ship receives a call for fire.

The Office of Naval Research sponsored development of ANSR and the Barrage Round by the Naval Surface Warfare Center Dahlgren Division. The new projectiles improve on existing 5" high-explosive ammunition in that they offer much longer range, higher speed, and a greater ability to damage or destroy targets. Greater accu-racy is achieved with a miniaturized guidance package that combines the Global Positioning System (GPS) with low-cost, commercial-off-the-shelf inertial sensors. This advanced system gets its small size and ability to with-stand the stresses of firing from recent advances in micro-electro-mechanical sensors.

The Autonomous Naval Support Round, commonly know by its acronym ANSR ("answer") is a rocket-assisted projectile-a rocket motor in the base of the shell increases the projectile's speed (and therefore its range) by augmenting the propulsive force of the conventional gun propellant. When the shell reaches its target, ANSR showers the area with pre-formed metallic fragments embedded in a composite matrix. ANSR was developed un-der Office of Naval Research sponsorship in a government-small business partnership between the Naval Surface Warfare Center Dahlgren Division and CAES. In Fiscal Year 2002, prime contractor Alliant Techsystems (ATK) invested corporate resources to demonstrate the range, lethality and guidance accuracy of the ANSR system.

The Barrage Round does not use a rocket, but instead achieves its higher velocities through a system of "sa-bots"-devices that hold a smaller caliber shell inside a larger gun tube and fall away from the shell as it leaves the muzzle of the gun. Sabots have long been used to achieve very high velocities in tank guns, but Barrage Round is the first to use the technology in firings from large-caliber Navy weapons. When it explodes at its target the Barrage Round dispenses a large number of flechettes-small, metal arrows. The Barrage Round was also developed under Office of Naval Research sponsorship in a government-industry partnership, this one led by the Naval Surface Warfare Center Dahlgren Division, SAIC, and CAES.

The United States Army's Atlantic Test Center and the Picatinny Arsenal also contributed valuable expertise and funds to these Navy programs.

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