GIAT M811

The M811 is an automatic, externally powered, single- or dual-fed autocannon firing NATO standard 25mm ammunition, designed by Nexter Systems (previously GIAT Industries).

GIAT M811
Type	Autocannon
Place of origin	France
Service history
Used by	See operators
Production history
Designer	GIAT Industries
Manufacturer	Nexter Systems
Specifications
Mass	113 kg (249 lb)
Length	2,640 mm (104 in)
Barrel length	2,160 mm (85 in)
Width	345 mm (13.6 in)
Height	370 mm (15 in)
Shell	NATO 25×137mm
Caliber	25 mm
Action	Externally powered, electric drive
Rate of fire	Low: 125 rds/min High: 400 rds/min
Muzzle velocity	1,360 m/s (4,500 ft/s)
Effective firing range	1,500 m (4,900 ft) APFSDS
Feed system	Dual Feed

History

The M811 was first shown in June 1983. Its intended use is in an air defense or direct-fire role, mounted on either naval or land platforms, replacing existing 20 mm cannon where applicable. The Model 811 has been installed on the Nexter Vextra 8 × 8 technology demonstrator for trial purposes. The turret installation was also provisionally selected for installation on the French Army's Vehicule Blindé de Combat d'Infanterie (VBCI) 8 × 8 Infantry Fighting Vehicle (IFV).

Description

Operation of the Model 811 is by an external electric motor that drives a camshaft lying inside the receiver. This shaft has a spiral cam groove that engages with a lug on the bolt, so that as the shaft revolves, the bolt is moved back and forth. The shaft is also geared to the feed mechanism, so that feed is in strict synchronization with the bolt's movements. A hang-fire safety device is provided. Fire modes are single shot, limited bursts or continuous bursts with a pre-selectable cyclic rate of fire at 125 or 400 rounds/min. The feed direction for the percussion-primed 25 × 137 ammunition can be manually or remotely selected, through an electrical feeder selection device. The first round fired following selection comes from the belt that has just been selected. The external power feature can be used for maintenance and training using dummy rounds. The Model 811 can fire all NATO standard 25×137 ammunition. Current ammunition available from Nexter Munitions include the following; High Explosive Incendiary Tracer (HEI-T), Target Practice (TP), Target Practice Tracer (TP-T), Armour-Piercing Discarding-Sabot Tracer (APDS-T) and Armour-Piercing Fin-Stabilised Discarding-Sabot Tracer (APFSDS-T). According to Nexter Systems, the accuracy of the Model 811 25 mm is such that all rounds fired will hit a 1.5 m diameter target at a range of 1,500 m.