The Slammer (Sholef) is a 155mm self-propelled howitzer variant of the Merkava with automatic loading system. The gun has a range of 40+ km with ERFB-BB. Two prototypes appeared in 1984 and 1986 but didn't entered production.

The Slammer is a heavily armored artillery gun mounted on a modified Merkava Mk 1 chassis. Many of these vehicles are Merkava Mk 1 that were retired after the Merkava Mk 2 and Merkava Mk 3 came into service. The Slammer has a long 52-caliber gun barrel that allows +10% range. Reload speed may be decreased to 1 for one minute every 10 minutes through use of an automatic loader. Ammunition racks are large. The Slammer is ready for autonomous operation (without an FDC) if the target's location is known within 15 seconds of a halt, using GPS, inertial navigation, and an internal fire control computer. The Slammer is also capable of direct fire on the move.

The Slammer 155 mm self-propelled howitzer is based on a modified Merkava MBT chassis fitted with a new welded steel turret, designed by Soltam Systems, that has a 155 mm 52 calibre ordnance with a total of 75 projectiles and charges being carried.

The ordnance is fitted with a fume extractor and a double-baffle muzzle brake. When travelling, the ordnance is held in position by a travel lock that is mounted on the forward part of the glacis plate and this is remotely operated from the crew compartment.

Firing an ERFB-BB projectile, the 155 mm 52 calibre ordnance has a maximum range of 40,000+ m.

The 155 mm 52 calibre ordnance and recoil system is of the companies well-proven type already used in its towed weapons. The breech block assembly is of the semi-automatic wedge type that contains an automatic primer feeding system that enables manual reloading of the primer without opening the breech. Turret traverse and weapon elevation is hydraulic, with manual controls for emergency use.

A maximum rate of fire of 9 rds/min can be achieved due to the automatic computerised loading system, and a burst rate of fire of three rounds in 15 seconds.

The high rate of fire can be achieved using the onboard ammunition supply or from ground-piled ammunition.

The loading cycle is operated by two turret crewmen only, with the commander operating the computer and charge loader.

The automatic loader has five main subsystems: projectile storage system; projectile transfer system; loading tray with flick rammer; charge loading tray and elevator for external charge supply; and projectile elevator for reloading the external storage or directly loading the gun.

The internal projectile storage contains 60 projectiles ready for automatic loading with the remaining 15 stored in other locations. The system enables the handling of all kinds of projectiles in use without any adaptation.

Charge loading is accomplished manually using a loading tray with the ignition primer being inserted automatically.

All systems have a manual back-up so that, in the case of failure, the loading system may be operated partly or completely manually by only three crewmen, so allowing a continuous firing rate of 4 rds/min.

The computer also controls the functioning of the gun. The Loader Control System (LCS) consists of five main units:

• The commander's panel provides the means for the commander to control the automatic loader and has a dedicated keyboard and supporting electronic circuits

• The Central Control Unit (CCU) is based on the 286 CPU-8086 and produces all of the system's logic equations. The unit transfers commands through the serial communications (RS-422) to the computerised units and controls the display on the commander's panel

• The Terminal Units (TUs) are based on the 8031 controller for purposes of independent control of the drive elements according to a functionally determined division. With the assistance of the terminal unit, a local mode can also be used in working with selected elements

• For guiding operators and making round identification and fuzing, the Operator's Panel (OP) includes an LCD display with fixed instructions and one dot matrix line

• The Loader Keyboard Panel (LKP) includes breech block closing switch, fire and local activation of the trays.

The main operational roles are: firing from internal storage; firing for elevator - ground-piled ammunition; loading from elevator - external pile; synthesising fire programs; unloading; manual firing; identification; and fuzing and checks.

Standard equipment includes an NBC system of the overpressure type and an inertial navigation and aiming system designed for autonomous operations.

According to Soltam Systems, the 155 mm/52 calibre ordnance and automatic loader, or parts of the system, could be installed in other self-propelled artillery systems and used to upgrade other self-propelled systems such as the US-designed and built 155 mm M109 and M44.