Non-Subscriber Extract
Current trends in cannon ammunition
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| 11 November 2005 |
By Anthony G Williams, Joint Editor of Jane’s Ammunition Handbook
Ammunition for aircraft cannon
Armour-piercing ammunition remains in use for special purposes, mainly for ground attack. The most notable examples are the US types with cores of Depleted Uranium (DU): the 30 × 173 mm PGU-14/B for the GAU-8/A gun in the A-10/A aircraft, and the 25 × 137 mm PGU-20/U for the GAU-12/U in the AV-8B.
Fixed-wing aircraft cannot use the more effective subcalibre Armour-Piercing Discarding-Sabot (APDS) and Armour-Piercing Fin-Stabilised Discarding-Sabot (APFSDS) ammunition used in ground guns because of the risk of pieces of discarded sabot hitting the aircraft or being sucked into the engines; there was one experiment with firing APFSDS rounds from the side-firing 40 mm Bofors guns in the AC-130, as these are sited behind the engines, but this was not successful. Helicopters are not subject to such restrictions, and the 20 × 102 mm M197 gun on the US Marine Corps AH-1 Cobra has been qualified to fire the MK 149 APDS rounds from the naval Phalanx Close-In Weapon System (CIWS).
Ammunition for ground-based guns
When armour penetration is the top priority, the supreme projectile type is the APFSDS, particularly in DU form, as used in the US Army's 25 × 137 mm M919 round for the M242 Bushmaster chain gun. As with HEDP, there were initially technical difficulties in getting APFSDS projectiles to perform in a rifled-barrel gun, in this case because their flight is destabilised by being spun, but these have been overcome, and this type of round (albeit with projectiles of tungsten alloy rather than DU) is now available for most 25 to 40 mm guns used in MICVs.
Significant exceptions to this are the British Army, which has been trying for some years to acquire an APFSDS loading for the 30 × 170 mm Rarden (it still relies on the less effective APDS), and the Russian Federation, whose 30 × 165 mm 2A42 and 2A72 guns also rely on APDS. However, Arsenal Company of Bulgaria has recently announced an APFSDS loading in this calibre, as has RWM Schweiz, which incidentally also offers FAPDS for the old Russian 23 × 152 B mm ZU AA round.
Ammunition for naval guns
Ammunition for the manually controlled 20 to 40 mm guns has largely followed the same path as that for army AA guns (indeed, it is usually the same ammunition). The old Second World War Oerlikon Type S, in 20 × 110 RB mm calibre, still lingers on for 'policing' duties, although it has largely been replaced by more modern rounds such as the 20 × 128 mm in the Oerlikon KAA. The 25 × 137 mm (Oerlikon KBA, Bushmaster), 30 × 170 mm (Oerlikon KCB) and 30 × 173 mm (Mauser MK 30, Bushmaster II) also feature, with the last of these becoming the main focus of recent development.
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