GCT 155mm The GCT 155mm is a modern self - propelled artillery vehicle currently in use by the armies of France and Saudi Arabia . It replaced the former Mk F3 155mm in French Army service . The GCT 155mm ' s primary advancement is that it incorporates and provides full armor and nuclear - biological - chemical ( NBC ) protection for its crew of four , while the former Mk F3 155mm offered no protection and could carry only two of its four crew members . Though 60 % heavier than the American M109 , the GCT 155mm is both faster , and incorporates a more sophisticated fire control system . The GCT 155mm saw combat with the Iraqi Army in the Iran – Iraq War . History . Though the French Mk 3 155mm would remain in production through the 1980s , by the early 1970s the French Army realized there was an urgent need for its replacement . The Mk . 3 155mm lacked an automatic loading system , but more importantly it lacked nuclear - biological - chemical ( NBC ) protection for its crew , and could carry only two of the four crew members needed to operate it ( the remaining two having to be transported in support vehicles ) . Development of the GCT 155mm began in the early 1970s , and the first production version , known as the AUF1 , was introduced in 1977 . About 400 have been produced , with 70 having been upgraded to the AUF2 variant . AUF1 . The GCT 155mm AUF1 is based on the AMX - 30 main battle tank ( MBT ) chassis and equipped with a 155mm 39 - caliber gun with an auto - loading system , giving a rate of fire of 8 rounds per minute , and a sustained rate of fire of 6 rounds per minute . It is also equipped with a roof - mounted 12 . 7mm anti - aircraft gun . The AUF1 has an effective range of 23 , 500 meters firing conventional rounds and 28 , 000 meters using Rocket Assisted Projectile s ( RAPs ) . The first production AUF1s were delivered exclusively to the Saudi Arabian Army , while the French Army received their first deliveries in 1980 , deploying the GTC 155mm AUF1 in regiments of 18 guns each . In addition , the Iraqi Army received a small number of GTC 155mm AUF1 variants in 1980 , which they employed during the Iran – Iraq War . Operational History . A battery of 8 AUF1s from the French Army ' s 40em Regiment d ' Artillerie was deployed in support of the Rapid Reaction Force on Mount Igman during the 1995 NATO bombing campaign in Bosnia and Herzegovina . The battery provided rapid counter - battery fire against Serb artillery units during the siege of Sarajevo , the long range of its guns allowing it dominate the surrounding terrain . AUF2 . The AUF2 is an improved turret for the GCT 155mm designed and built by GIAT . The AUF2 155mm howitzer and turret are designed for integration onto a wider range of armored chassis such as AMX30 , Leopard 1 , Arjun and T - 72 . It was initially developed to upgrade the GTC 155mm AUF1 self - propelled howitzers then in service with the French Army . The French Army has procured approximately 70 AUF2 turrets and mounted them on the AMX30B2 chassis . Improvements in the AUF2 include an all - new automatic round and charge feed system and a new 52 - caliber artillery tube . New charges and rounds are also available for the AUF2 . The AUF2 is equipped with a 7 . 62mm anti - aircraft machine gun located at the roof of the turret . The AUF2 turret , including the gun and loading systems , weighs nearly 19 tons . Compared with the AUF1 , the AUF2 offers a significantly improved range of 42 km , a higher rate of fire of 10 rounds / minute and multiple rounds simultaneous impact . In use , the weapon system has been found to have greater reliability , accuracy and ease of maintenance .