battery command vehicle (BCV). Giant Bow II a.k.a. Shengong-II – This is a more modern version of the Giant Bow and is offered for export since 2005. Apart from the 23 mm guns, it also comprises TY-90 missile launchers and a 3D radar. Type 87 – Upgraded version with twin 25 mm guns for 25x183B ammunition such as the PG87. After a failed initial design, an improved design was developed in 1979 and ready for evaluation in 1984. The Type 87 gun was accepted for service in 1987. It has the same layout as the original model and consists of two automatic, recoil-operated cannons, a two-wheel cartridge, a Type 86 infrared tracking sight and two 40-round ammunition magazines. The Type 87 fires in either single shot or burst mode, with a cyclic rate of fire of 600~700 rounds/min and has a muzzle velocity of 1,050 m/s. PGZ95 – self-propelled version of the Type 87. Iran Mesbah-1 – Iranian-made air-defence and anti cruise missile system with four ZU-23 mounts. For the first time presented in 2010. ZU-23-6 (unofficial designator) – Similar to the Mesbah-1 but with only 6 instead of 8 barrels. This was probably the pre-series model of the Mesbah-1. Vietnam 23mm-2M (alternatively 23-2M) – an Israeli-Vietnamese co-developed gun turrets solution for the Vietnam Coast Guard patrol vessels. Upgrades include a cabin for the gunner, electromechanic turn system & modern controlling systems as alternatives to the legacy pure-mechanical systems. Ballistic computer & fire-control system are optional. 23mm-2ML (or 23-2ML) – mostly equivalent to the above 23-2M except the addition of an optronics sensor and laser rangefinder for better targeting performance & accuracy as well as the potential electronic fire-control system integration. Projects to "mechanize" the ZU-23-2 consist of the installation of the platform on Soviet ZIL-131, Russian KamAZ-43118 6x6 trucks or the American M548 tracked cargo carriers are chosen and commissioned by the Vietnam People's Army. Solutions for a remotedly/automatically-controlled ZU-23-2 weapon station are also being developed. General characteristics Overall dimensions in firing position Length: 4.57 m (15 ft) Width: 2.88 m (9.44 ft) Height: 1.22 m (4 ft) Weight: 0.95 tonnes (2,094 lbs) Armament: two 2A14 Afanasyev-Yakushev 23x152mm (.90 in) autocannons Barrel length: 2 m (6.5 ft)/ 87.3 calibers Muzzle velocity: 970 m/s (3,182 ft/s) Projectile weight: 186 g (6.27 oz) Rate of fire Cyclic: 2,000 rounds per minute Practical: 400 rounds per minute Effective range: 2-2.5 km (1.24-1.55