The armor is augmented by spall liners, and the same overpressure NBC system as the Merkava Mk.III is fitted. There is also a back-up collective NBC system. The running gear consists of six unevenly spaced rubber-tired roadwheels on each side, and five return rollers, the second from the rear of which is noticeably larger than the others. The drive sprocket is forward, and the conspicuously spoked idler is rear. These may be partially obscured by track skirts, of which the Merkava Mk.III has ten panels, with a wavering underside, and little coverage of the sprocket or idler. 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.