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XM-29 OICW Description.
The XM-29 is a combination weapon, which has the 20mm semi-automatic, magazine fed grenade launcher as its primary part, and the 5.56mm compact assault rifle as its secondary part. Both parts are assembled into the single one-man portable unit, with the addition of the target acquisition / fire control system (TA/FCS), which is an essential part of the whole system. The XM-29 will become an integral part of the future Land Warrior system, capable of communicating with the other parts of this system, including the tactical computers and helmet-mounted displays.

The grenade launcher is capable to fire in semi-automatic mode only, and is gas operated. It has a bullpup layout with the detachable box magazine located in the butt of the weapon. The rifled barrel is used to launch the 20mm grenades up to the 1000 meters range with good accuracy. In the standard configuration most of the fire controls for the grenade launcher part are located on the rifle part, including the single trigger for both firing modules. It is quite possible, however, that the separate stock will be developed for the grenade launcher part, so it will be possible to use it without the rifle part attached. The launcher has the provisions for the TA/FCS system to be mounted on its top, and the appropriate interfaces, so the data provided from the TA/FCS can be used to program the 20mm grenade fuses. These fuses, used for the 20mm HEAB ammunition, has multiple mode of detonation, including the direct impact mode and the Air Burst mode. In the latter mode the fuse is pre-programmed to explode the warhead at the preset range, which is calculated during the flight by counting the number of the grenade rotations. This allows do defeat targets without the direct impact, using the blast and fragmentation effect of the high explosive warhead. This is a major advantage over the present small arms, which in most cases require the direct hit on the target to be effective, as it allows for greater aiming errors, and also makes possible to defeat targets in defilade, like the trenches and so. The high explosive warhead also has the advantage of not being dependent on its velocity to be effective, so unlike with the bullets, its effectiveness does not decreased with the increase of range.