Italy purchased 221 155 mm M109s from the USA without armament. The armament was manufactured and installed in Italy by Otobreda (at that time known as OTO Melara) and issued to the Italian Army. In addition to taking delivery of the 221 155 mm M109s without armament, the Italian Army also took delivery of 62 complete 155 mm M109A1B systems.

In 1970-71 Otobreda produced a long-barrel version of the 155 mm M109 capable of firing FH-70 projectiles to a maximum range of 24,000 m. At that time there was no Italian Army requirement for this increase in range but early in 1984 the Italian Ministry of Defence ordered three examples of this for extensive trials.

The trials were successful and a decision was taken in 1986 to upgrade a total of 280 Italian Army 155 mm M109 series self-propelled weapons to the 155 mm M109L configuration. The first batch of 32 155 mm M109Ls was completed in 1986 and final deliveries were made in 1992.

There have been no known export sales of this upgrade package. The 155 mm 39 calibre ordnance used in this upgrade is also used in the Otobreda 155 mm 155/39 TM howitzer upgrade which is no longer being marketed. Details were given in Jane's Armour and Artillery Upgrades 1997-98 pages 99 to 100.

In the longer term the Otobreda 155 mm M109Lwill be replaced in some units by the Krauss-Maffei Wegmann 155 mm 52 calibre PzH 2000 self-propelled artillery system.

The hull of the M109 has been modified to M109A3 standard which is compatible with the new elevating mass and the aiming system of the M109G.

The main change on the M109L is the replacement of the existing 23 calibre barrel with a 39 calibre barrel. Externally this is configured to the M109 mounting, but internally it is ballistically similar to the FH-70 configuration and can thus fire existing M107 ammunition or FH-70 ammunition. Firing L15 HE projectiles the M109L has a maximum range of 24,000 or 30,000 m with assisted ammunition.

In addition to the installation of a new ordnance, the following have been modified:

(1) recoil buffers and run-out buffer

(2) cradle to fit the new ordnance

(3) replacement of the equilibrator and elevating cylinder

(4) barrel clamp to fit new barrel.

The new 155 mm 39 calibre barrel is fitted with a revised muzzle brake, with the maximum recoil increase on the M109L being only 100 mm. The existing breech and breech ring of the original M109 have been retained.

The elevating mass, as modified, is interchangeable with that on the basic M109, furthermore the mechanical interface between the elevating mass and saddle, as well as the mountings of the optical device, do not require any modification.

To reduce operator fatigue and increase rate of fire, a rammer can also be fitted to the M109L system.

Status

Conversions complete. In service with the Italian Army. There are no known exports of the upgraded M109L system.