The origins of the Denel Land Systems 105 mm Light Experimental Ordnance, sometimes referred to as the LEO, can be traced back to 1995. This was when the South African Defence Force set the following design goal to Denel Land Systems to 'Develop the technology for a light gun with a light logistic load that will equal or better the range and equal or better the terminal effect of current 155 mm light guns.'

A ballistic testbed was completed and test fired in 1997, with the first complete example of the 105 mm Light Experimental Ordnance completed in 2001. This has since undergone extensive firing trials at the Alkantpan range in South Africa, during which some 350 rounds were fired.

The Denel Land Systems 105 mm Light Experimental Ordnance was first revealed late in 2000 and first exhibited overseas during the IDEX 2001 exhibition held in Abu Dhabi in March 2001.

Denel Land Systems stress that this is a technology demonstrator and is not representative of a type classified and ready for production 105 mm artillery system.

If adopted for service it will probably be given the designation of the GV7 or G7 for international marketing purposes. Its primary role is close support.

According to Denel Land Systems, there is no other artillery system in the world with the capabilities of the 105 mm Light Experimental Weapon which includes a maximum range of 30,000 m.

This is similar to that of 155 mm/39 calibre artillery systems with the new 105 mm high-explosive artillery projectile, having a lethal area of 1,900 m2 against targets. This is claimed to be better than a first-generation 155 mm artillery projectile.

A 105 mm Light Experimental Weapon together with 100 rounds of 105 mm ammunition currently weighs 6,000 kg which is being reduced still further. According to Denel Land Systems this should be compared to more than 10,000 kg for a 155 mm system plus a similar number of rounds. Because of the lighter 105 mm ammunition, the crew requirement is reduced and it is also suitable for the 'lighter built' soldier.

The first example of the 105 mm Light Experimental Ordnance weighs 3,800 kg and the development team is now working to reduce this to 2,500 kg making it easier to deploy.

According to Denel Land Systems the reduction in weight is especially important for fielding in peacekeeping operations or for early entry forces/light forces for rapid support of allies and for close fire support.

The 105 mm Light Experimental Weapon was originally developed using funding from the South African Defence Force. This has now expired and the programme is currently being funded by Denel Land Systems.

This weapon system has also been referred to as the 105 mm Artillery Ballistic System. In addition to the conventional split trail carriage used for the prototype system, a number of other carriages are under consideration.

It is expected that in 2008 Denel Land Systems will be awarded a contract from Armscor, for full scale development of a complete 105 mm artillery system.

LEO will form the basis of the new 105 mm artillery system which will also include its family of ammunition, on board fire control systems plus logistics and training.

This system is called the Advanced Multi-role Light Artillery Gun Capability (AMLAGC) and Phase I is expected to run through to 2009 and include man rating of the existing LEO 105 mm ordnance and its ammunition as well as starting development of the new gun.

This is expected to be followed by Phase II which will include the construction and test of a complete 105 mm weapon, interface for mounting this on other chassis and final qualification of the weapon and its ammunition.

The 105 mm Light Experimental Ordnance has a split trail carriage of high-strength steel and when deployed in the firing position is supported by a jack lowered under the forward part of the carriage and by the spade on the end of each trail.

The carriage is provided with an adjustable towing hook for towing by 4 × 4 vehicles and lifting hooks for transportation slung under a helicopter.

The 105 mm autofrettaged ordnance is 52 calibres long, or 57 calibres when fitted with the advanced muzzle brake, and has a rifling twist of 1:22. The high-efficiency pepperpot muzzle brake has special Laval-shaped nozzles and is rifled on the inside, which effectively adds five calibres to the barrel.

The ordnance has a fixed recoil length of 1 m with a gas type counter system being fitted. Counter recoil is also used to retract the 105 mm ordnance using the hydraulics of the traverse and elevation system.

The breech mechanism is of the semi-automatic swing and slide type.

The traverse and elevation system of the 105 mm Light Experimental Ordnance consists of the following key parts:

• Hydraulic system fitted with proportional control valves

• Hydraulic elevation cylinders with integrated pneumatic equilibrators

• Traverse gearbox with hydraulic drive motor

• Hydraulic hand pump to supply hydraulic pressure manually

• Electrical driven hydraulic pump to supply the hydraulic pressure required

• Hydraulic hand pumps for manual elevation and traverse of the gun

• Traverse gearbox fitted with a clutch for rapid traverse of barrel from travelling to the firing position

• Joystick control fitted for controlling elevation and traverse of the gun

The bottom carriage is of the split trail type made of high-strength steel. The two main wheels are mounted on a trailing arm suspension and are adjustable for height. The trails are provided with dig in spades designed for use in hard ground.

Mounted on the forward part of the carriage is a large manually operated stabilising platform that is lowered to the ground before firing commences. There is also a barrel clamp on the trail legs to clamp the barrel when the gun is towed in the travelling position.

The high-strength steel saddle is of the trough type with self-adjustable type trunnion bearings. The gun control equipment is also mounted on the saddle on the left side.

An adjustable towing hook is provided to allow towing by a 4 × 4 or any 5-ton type of vehicle and lifting hooks can be fitted to allow transport of the gun by helicopter. The weapon can be towed on roads up to a maximum speed of 100 km/h with the ordnance in the firing position or locked in position over the closed trails.

To power the onboard electrical equipment, two 12 V maintenance-free batteries are fitted together with electrical harnesses, control boxes, tail lights, indicator lights and brake lights.

The basic model is fitted with telescopic sight for direct fire up to a range of 3,000 m and a trunnion-mounted optical panoramic sight with compensating mechanism for trunnion cant for indirect fire. This is installed on the left side of the weapon. Aiming posts and beta lights are stored on the gun.

The advanced model will retain the telescopic sight for direct fire up to a range of 3,000 m but will also have a ring laser gyro, display unit and an automatic laying system. This has already been proven by Denel Land Systems, on other towed and self-propelled artillery systems.

The basic model is fitted with a manual loading system (hand ram) which enables the weapon to be loaded at all angles of elevation. The improved model will be fitted with a positive chain-push rammer, which will be hydraulically operated and controlled. This will be able to ram both the projectile and charge at any elevation.

Firing Denel Munitions standard ammunition a maximum range of 24.6 km will be achieve which increases to 29.3 km with base bleed and 36 km with a Velocity-enhanced Long-range Artillery Projectile (V-LAP).

The new family of Igala 105 mm ammunition consists of the projectile which can be fitted with an interchangeable boat tail or base bleed unit and a unimodular charge system which gives a maximum pressure of 427 Mpa.

The ammunition suite includes HE (natural fragmentation), HE (pre-formed fragmentation), practice, smoke (visual and IR screening) and illumination (visual or infra-red). In addition a Armour Piercing Fin Stabilised Discarding Sabot (APFSDS) round has been tested with a m/v of 1,700 m/s.

In fact, development of the baseline 105 mm family has already been completed with the last round, the V-LAP still under development. The later leverages off of a 155 mm V-LAP which has already been produced in production quantities for an export customer.

It should be noted that all of this 105 mm ammunition is IM compliant and according to Denel is backwards compatible with existing 105 mm weapons.

Trials have already shown that the 105 mm PFF has a greater lethal radius that the older US 155 mm M107 HE projectile but at the same time a 76% smaller danger area.

A locally developed Denel Arachnida (or Selex LINAPS) will be fitted to reduce into action times and improve accuracy with the former already standard on South African G5/G6 guns and 127 mm (40-round) Valkiri Mk II artillery rocket launcher.

Ammunition is of the separate loading type, projectile and charge and the system has a maximum rate of fire of six rounds a minute. Various fuzes, including the new Fuchs electronics multi-option fuze have been tested with the 105 mm Light Experimental Ordnance. Fuze options include impact fuze M841, proximity fuze M8513 and time fuze M9220.

According to Denel Land Systems, at 75 per cent of maximum range, dispersion is 0.3 per cent of range and 0.5 mil in deflection.

During the full scale development phase, Denel Land Systems stated that the following improvements will be addressed:

• Development of a base bleed unit to increase the range of the system to more than 30 km

• Further weight reduction making use of high-strength materials

• Methods of further improving accuracy and dispersion

• Adding an automatic laying system on models to be fitted with a laser inertial laying system

• A load-assist system

• Mobility and deployability improvements

• Changes to make it possible to fire other types of ammunition for training purposes

In addition to the standard split trails of the technology demonstrator 105 mm LEO, other carriages are also under consideration.

In addition to the development of the 105 mm LEO, Denel Land Systems teamed with General Dynamics Land Systems of the USA have developed a self-propelled (SP) version.

This consists of a LAV (8 x 8) chassis fitted with a new turret armed with the same 105 mm ordnance as fitted to the LEO.

Development of this is continuing in the areas of gun control, ammunition handling, protection, integrated command and control and on board ammunition setting.

Full details of this system are given in a separate entry.

Denel Land Systems have also carried out some studies on a ultra lightweight version of LEO 105 mm using advanced materials which would have a new carriage and weigh about 2,000 kg.

Using the upper part of LEO 105 mm a truck mounted version (6 x 6) could be developed which would also have space for the crew and some ready use 105 mm ammunition.