Late in 2000, RDM Technology started firing trials of its private venture M109L52 self-propelled artillery system fitted with 155 mm/52 calibre Extended Range Ordnance (ERO).

The new RDM Technology 155 mm/52 calibre M109L52 is aimed at existing users of the US United Defense M109 series of 155 mm self-propelled artillery systems, whose original development can be traced back well over 40 years.

RDM Technology has already entered into a co-operation agreement with the Hellenic Arms Industry (EBO) to offer not only the M109L52 but also the 105 mm M101 and 155 mm M114 towed artillery system upgrades to the Hellenic Army.

The new M109L52 is a logical development from work that RDM Technology has carried out on a variety of towed and self-propelled artillery systems over the last few years for both the home, and increasingly, for the international export market. Details of the M109 upgrades are given in a separate entry.

The latest RDM Technology M109L52 upgrade has many improvements over the earlier M109L47 developed for the United Arab Emirates and is fitted with a new 155 mm/52 calibre ERO (Extended Range Ordnance). The first model of the 155 mm/52 calibre M109L52 used an RO Defence ordnance as fitted to the latest version of the AS90 self-propelled artillery system.

The second and third prototypes of the M109L52 are fitted with a German Rheinmetall Weapons & Munitions 155 mm/52 calibre barrel as used in the German Krauss-Maffei Wegmann PzH 2000 self-propelled artillery system.

For the new application the ERO has been fitted with a new breech ring, RDM Technology designed multislotted muzzle brake and a new breech mechanism. Also fitted is an automatic 10-round primer magazine with laser ignition being an alternative.

The existing M109 cradle and recoil system has been modified and a remote travel lock, operated by the driver, fitted as standard. This enables the system to come into action without one of the crew leaving the vehicle so reducing time and allowing the driver to remain under complete armour cover.

The maximum range of the M109L52 depends on the type of projectile and charge combination but is typically 40 km with an Extended Range Full Bore - Base Bleed (ERFB-BB) projectile.

To obtain a higher rate of fire and to reduce crew fatigue, an Austrian Intertechnik flick rammer and German Rheinmetall Landsysteme (previously KUKA) Ammunition Handing Kit (AHK) has been installed. The German Army has already taken delivery of 262 of the latter for its M109A3G systems. Burst rate of fire is claimed to be three rounds in 10 seconds. New propellant racks have also been installed.

The upgraded M109L52 has a number of other improvements including installation of the BAE Systems Laser Inertial Artillery Pointing System (LINAPS) of which 137 have been supplied for installation on 105 mm Light Guns of the British Army.

The turret traverse and weapon elevation system has been upgraded and a muzzle velocity radar mounted over the 155 mm/52 calibre ordnance. A laser range-finder for the direct fire role is also fitted.

An auxiliary power unit and the NBC/air conditioning system are mounted on the bustle. The current 450 hp 8V-71T Detroit Diesel engine coupled to an Allison Transmission XTG-411-4A automatic transmission is retained but a more powerful diesel engine can be fitted if required to give the system a higher power-to-weight ratio.

The normal M109 has a crew of six people but for the upgraded M109L52 this has been reduced to four, commander (who also lays the weapon), assistant gunner, loader and driver.

The new 155 mm/52 calibre ordnance gives the M109L52 an enhanced range capability as well as faster response time which in turn improves its battlefield survivability against counter battery fire as it can come into action, complete its fire mission and re-deploy before counter battery fire arrives.

RDM Technology have stressed their M109L52 is a modular upgrade with the customer only taking those parts that meet their operational requirements, or more likely, budget considerations.