73 mm ammunition for SPG-9 recoilless gun

spring out once the projectile has left the muzzle. On target, the shaped warhead is initiated by a VP-9 piezoelectric point impact fuze via an igniter in the base of the shaped charge. The PG-9 warhead can penetrate 300 mm of armour while the PG-9N can penetrate 400 mm. Maximum range of both projectiles is 1,300 m while the direct fire range at a target 2 m high is 800 m. Muzzle velocity in both cases is 435 m/s. The latest round is the PG-9VS for which the maximum direct fire range is increased to 1,300 m. A complete round weighs 3.2 kg and overall length is 920 mm. The span of the fully opened guidance fins is 190 mm. By contrast, the basic 73 mm FRAG-HE rounds, a later development, do not have a rocket motor. There are two basic types of FRAG-HE round, the OG-9V and OG-9VM, differing only in the weight and type of explosive in the 309 mm long cast-iron warhead on the projectile. The OG-9 FRAG-HE projectile warhead used with the OG-9V round contains 753 g of TNT while the OG-9M projectile used with the OG-9VM round contains 655 g of TD-50 (TNT/dinitronaphthalene). In both cases the explosive is ignited by a nose-mounted GO-2 or O-4M point detonating fuze. Flight stabilisation is provided by six fixed fins on the end of a perforated steel tailboom which also contains a tracer element. The propellant employed is 4BN40. The latest FRAG-HE round is the OG-9VM1 with a total weight of 5.35 kg. Two further 73 mm FRAG-HE rounds are Bulgarian developments, the OG-9BG and OG-9BG1, with OG-9G and OG-9G1 projectiles respectively.