the same time force the driving band to engage with the twelve rifling grooves. The rifling imparts stabilizing spin to the projectile. The barrel has a service life of about 400 rounds. Ammunition The grenade launchers fire a series of special 40 mm grenades. Originally, the main grenade was the VOG-15 (7P17) fragmentation grenade. This was superseded by the steel-cased VOG-25 fragmentation grenade. The VOG-25 has a lethal radius of six meters. Rounds for the muzzle-loaded GP-25 consist of a single piece containing both propellant and warhead, unlike the more traditional two piece casing-and-projectile design of the comparable American 40x46mm round used in breech-loaded grenade launchers, such as the M203. A bouncing grenade, the VOG-25P, is also available. On impact, a small charge in the nose of the grenade is detonated; this raises the grenade 0.5 to 1.5 m in the air, before an impact delay fuse detonates it. The VOG-25P also has a lethal radius of six meters. New generation rounds VOG-M and VOG-PM with an increased effectiveness not less than 1.5 times are now serially available. Smoke grenades are also available. The original GRD-40 grenade has been replaced by a series of grenades designed for use at different ranges. These are the GRD-50, GRD-100 and GRD-200 for use at 50, 100 and 200 meters respectively. They are capable of producing a 20 cubic meter cloud of smoke that lasts for one minute in winds of up to five meters per second. A CS gas grenade called the Gvozd ("Nail") and a baton grenade are also available. Grenades Fuse arming range: 10–40 m (33–130 ft) Fuse self-destruction time: 14–19 s VOG-25 specifications: Weight: 250 g (0.55 lb) Warhead: 48 g of A-IX-1 explosive. VOG-25P specifications: Weight: 278 g (0.61 lb) Warhead: 37 g of TNT. GRD-50/100/200 specifications Weight: 265 g Warhead: 90 g Variants GP-25 Kostyor GP-30 Obuvka GP-34 Users : Used by Caatinga infantry : Made under license by Arsenal AD as the UBGL and the UBGL-1. : Made by STC Delta. : Used for the AK-74M. : Mobile Brigade Corps : Used by IRGC : Lithuanian Armed Forces : Made under license by Zastava Arms as the PBG – 40 mm and the PBG 40 mm M70. : Uses both GP-25s and GP-30Ms. See also BS-1 Tishina QLG-10 RGM-40 Kastet grenade launcher is a stand-alone version of GP-30 grenade launcher Wz. 1974 Pallad grenade launcher References External