Ammunition for 57 mm L/70 Bofors guns 57 mm HCER-BB

use against air targets, including sea-skimming anti-ship missiles. It uses a projectile with a prefragmented high-quality steel body fitted with a proximity fuze. The fuze operates on the Doppler principle and includes the same electronics used in the proximity fuze fitted to the 40 mm L/70 PFHE Mk 2 round (qv), thus providing increased triggering distances and increased resistance to ECM. When the fuze functions, either as a proximity fuze or on impact, the projectile body detonates to produce approximately 3,500 fragments, 1,200 of which are integral 3 mm tungsten pellets with high penetration capabilities. The pellets are carried around the inner wall of the projectile body, packed around the filling which is 380 g of Hexotonal. This increased sensitivity together with the increased number of fragments and 3 mm diameter tungsten carbide pellets greatly increases the kill effect against all types of aerial target. The time function causes the 3P fuze to act as a normal time fuze. The accuracy of the time setting is less than 0.5 per cent of the time of flight and typically 0.2 per cent. For a typical example, the clock's accuracy (together with the deviation in muzzle velocity) gives a dispersion of 7 m at a range of 1,500 m. The Impact mode is selected when a high-hit probability is expected. There is a 0.3 ms post impact delay permitting the projectile to penetrate the target before detonating. In the Armour mode the safety/arming device is prevented from arming, so that on impact with a hard target the 3P projectile will shock ignite with a delayed low order detonation. The fuze will operate on targets such as a 2 mm dural plate. When no mode selection is made or the range to a target is not known, the 3P fuze will operate as a conventional proximity fuze with an impact function.