The development of guns has almost reached a plateau in terms of reach but there has been revolutionary development in gun ammunition to meet the requirements of longer reach, lethality and accuracy. The modern gun ammunition can be used from land, sea or air, depending on the type of platform.

Classification of the calibre of guns or ammunition is difficult as every country and manufacturing company has its own system. In the Indian Artillery, the classification was earlier based on the calibre of the gun and the ammunition was named accordingly. The field gun was around 25 pounder/105mm, the medium gun was 5.5 inch/130mm and the heavy guns were 7.2 inches. This distinction has been somewhat blurred with the employment of heavy firepower in all phases of offensive and defensive operations. Accordingly, 155mm is an accepted calibre across the board for field artillery. However, there are a variety of ammunitions termed as “medium calibre” depending upon its role and employment. The development of guns has almost reached a plateau in terms of reach but there has been revolutionary development in gun ammunition to meet the requirements of longer reach, lethality and accuracy. The modern gun ammunition can be used from land, sea or air, depending on the type of platform.

Medium-Calibre Ammunition

Many companies are developing and manufacturing many types of state-of-the-art medium calibre ammunition to be used from land, sea and air.

ATK

ATK produces a complete family of mediumcalibre tactical and training ammunition which can be fired from Apache helicopters, A-10 Thunderbolt II aircraft, Bradley infantry fighting vehicles, ship platforms, etc. They are in the calibre range of 20mm, 25mm and 30mm rounds which can be effectively used in a variety of roles like anti-armour, anti-materiel, anti-personnel, ground suppression, air defence, and shipboard-defence applications.

20mm x 102mm: ATK produces a full spectrum of 20mm x 102mm ammunition for air, ground and sea platforms for armour piercing, anti-materiel and personnel role. The ammunition is lethal, has good penetration and is very accurate. It can be effectively used from fixed-wing aircraft for combat applications to support air-to-air and air-to-ground missions; rotary-wing applications for air-to-ground missions and against today’s modern littoral and antiship threats. This ammunition can also be used in a ground-based defence system to counter rocket, artillery and mortar attacks and against speeding cars loaded with explosives. The rounds can be fired from the M39A2, M61A1, M197 and M621 cannons. The penetrator with enhanced lateral effect (PELE) round version offers a superior fragmenting projectile without the use of high explosives. It is effective against air targets as well as light armour and material targets.

25mm: ATK is the world’s leading supplier of combat proven, low-cost 25mm x 137mm ammunition which is extremely effective in anti armour, anti-materiel, antipersonnel, and fire suppression roles. The 25mm Bushmaster ammunition provides infantry fighting vehicles, ship self-defence systems and air defence platforms with the firepower necessary to meet a variety of threats. This ammunition may be fired from the ATK Bushmaster M242 chain gun, the Oerlikon KBA, GAU-12/U cannon or any other North Atlantic Treaty Organisation (NATO)-qualified 25mm weapon system. The ammunition meets or exceeds all the US Government performance requirements and is the only 25mm ammunition to have obtained NATO certification.

30mm x 173mm: This family of ammunition builds on the experience of ATK which has produced over 100 million rounds of 30 mm GAU-8 ammunition. This new generation of ammunition for ATK’s Mk44 cannon has been developed for the US Marine Corps expeditionary fighting vehicle. Mk44 cannon and 30mm ammunition can also be used with infantry fighting vehicles and naval platforms. It can be used effectively in armourpiercing and anti-personnel roles.

30mm x 173mm Air Burst Munition (ABM) System: The system provides the capability to burst a 30mm projectile at a precise point in space resulting in increased effectiveness against targets in defilade. The ATK ABM system comprises of the ATK 30mm Mk44 Bushmaster cannon employing an integrated fuse setter in the feed system; an ABM fuse setter module in the gun control unit; an ABM ballistic algorithm integrated into the platform fire control unit; and the Mk310 programmable airburst munition (PABM). The PABM can function in air burst, point detonating and point detonating delay modes. The projectile has proven penetration capability and is significant behind armour effects against lightly armoured vehicles. The ATK Abm system is also capable of being retrofitted into existing Mk44 cannons. It can also be easily integrated into land and sea platforms using ATK’s Mk44 cannon. ATK airburst system can be integrated into future and legacy platforms.

Light weight (LW) 30mm ammunition: ATK provides the US and its allies with a multi-service family of LW 30mm ammunition which was developed and fielded for the M230 chain gun on the AH-64 Apache helicopter. Combat proven in Operations Just Cause, Desert Storm and in Afghanistan, LW30mm high explosive dual purpose has demonstrated excellent armour penetration at ranges from 150 to 2,000 metres, effectively defeating the infantry fighting vehicle threat. Because of its light weight, small volume, and moderate recoil, LW30mm ammunition is ideal for helicopters, light ground vehicles and shipboard applications. Proven effective against light armour and materiel targets, it provides suppressive firepower at ranges equal to those of the hellfire or tube-launched, optically-tracked, wire command-link guided (TOW) missile, making it capable for defeating armour as well as providing wide-area lethality.