APFSDS AMMUNITION - ARMOURED PIERCING FIN-STABILISED DISCARDING SABOT

APFSDS (Armoured Piercing Fin-Stabilised Discarding Sabot) ammunition is a type of anti-tank round. It uses kinetic energy to penetrate armoured vehicles, and is often referred to as a KE round. A fin stabilised sub-projectile or sub-calibre 'dart' of very dense material such as depleted uranium (APFSDS - DU) or tungsten steel (APFSDS - TS) is fired at very high speed (hyper-velocity). The sub-projectile has a high length to diameter ratio, and is often referred to as a 'long rod penetrator'. By encasing the sub-projectile in a lightweight sabot jacket the sub-projectile is able to be fired from a much larger calibre gun. The sabot in effect 'seals' the space between the barrel lining and the sub-projectile.

The difference in calibres between the gun barrel and the sub-projectile means that a disproportionate high charge/propellant level to projectile weight/drag occurs. This results in massive energy transfer to the low drag sub-projectile, the sabot ensuring all energy is transfered to the 'dart'.

The sabot round rapidly attains hyper-velocity in the gun barrel. As the sabot round leaves the muzzle of the gun, the sabot jacket is shed from the sub-projectile 'dart' by its own drag.

The sub-projectile's hyper-velocity ensures that it strikes its target with devestating impact. By using very dense materials in the sub-projectile the stored kinetic energy is magnified greatly. The terminal effect of the sub-projectile striking the target sees huge kinetic energy release. In miliseconds the sub-projectile punches through the target armour, instantaneously generating massive heat and pressure. As the long rod penetrator enters the vehicle friction with the armour plate creates burning incandescent spall which sprays the interior. The burning spall has an explosive effect.

HIGH PENETRATION PERFORMANCE OF KINETIC ENERGY ROUNDS

KE rounds where used extensively in the Gulf War with great battlefield success. Combat experience with APFSDS rounds has shown that penetration generally causes a catastrophic interior explosion, devastating the crew compartment and often igniting stored ammunition.

The US Army tank crews nicknamed their depleted uranium M829A1 Armor Piercing, Fin Stabilized, Discarding Sabot-Tracer (APFSDS-T) the 'Silver Bullet'. The hyper-velocity M829A1 round allowed M1A1 Abrams crews engaged targets at very long ranges. The penetration characteristics of tank gun APFSDS darts was so great that enemy tanks could be engaged behind sand berms, the sub-projectile penetrating between ten to thirty meters or sand and still achieving a hard kill. It has been reported that a single M829 round pentrated and destroyed two Iraqi T-72. Apparently they happened to be in line, the 'silver bullet' simply punching through the first tank to hit the second

LONG RANGE TANK GUNNERY

During the Gulf War the open desert terrain and extensive use of thermal imaging weapon sights ensured that maximum engagement ranges were possible. Tank gunnery demonstrable reach a new zenith. Modern integrated fire control computers are highly sophisicated and able to link the electro-optical systems/sensors to a gyroscopic stabilised main gun. Laser range finders deliver pin point range calculations whilst other ballistic properties such as windage, barrel wear, air and barrel temperature are also calculated. The fire control systems therefore achieve 'first round' hit probability on a regular basis

Hyper-velocity APFSDS rounds have significantly increased the leathal range of tank fires, and combined with improvements in tank gunnery this has meant that combat engagement ranges have been dramatically increased. During Operation Desert Storm a British Army Challenger tank achieve the longest range confirmed tank-to-tank kill at 5100 meters or 5.1km with an rifled 120mm APFSDS 'Charm' depleted uranium round.

DEPLETED URANIUM TOXICITY

The use of toxic depleted uranium in kinetic energy weapons has become contentious following reports from both the Gulf War and the Balkans. DU rounds released environmental toxins in the form of depleted uranium micro-spall dust particles. The suggestion is that this DU dust may well be the main contributing factor behind 'Gulf War Syndrome' and other health issue related to soldiers who served in these theatres. The military are now faced with a dilemma between the operational needs of combat effectiveness, force integrity and survivability against the very real residual health risks to unprotected personnel operating in theatre. Although some armies have considered returning to the use of tungsten steel, such a degradation in combat performance is deemed unacceptable by many, and the DU APFSDS round are still manufactured and used.