The baseline version of the Bofors 57mm (2.2 in) L70 gun was the Mark 1, first introduced into service with the Spica-class fast attack craft (FAC) of Swedish Navy in 1966, it has a rate of fire of 200 rounds per minute and a 40-round magazine in the gun turret with a further 128 rounds stowed inside. With minor modifications, the Mark 1 guns could use ammunitions developed for the Mark 2 gun. The Swedish built MK 100 Naval Gun system delivers high rates of fire with extreme accuracy against surface, airborne and shore-based threats. In the littoral scenario the gun must have the capability to engage threats that were impossible to engage with conventional gun systems. Survivability in such an environment requires an extremely flexible weapon system. The 57mm Mk110 has this flexibility, which is proven by the fact that it is the deck gun of choice for the US Coast Guard’s National Security Cutter and offshore patrol cutter classes of ships, as well as for the US Navy’s LCS ships.
A high rate of fire and immediate switch capability provide superb survivability and tactical freedom at all levels of conflict. Its 3P ammo can be programmed for optimised effect against any target, including airburst patterns for new threats that were previously impossible to engage. The gun is controlled by a single remote operator via the Fire Control System. As a backup, it can also be controlled from Local Control Equipment located anywhere on the ship. A muzzle velocity radar attains the highest accuracy, as well as making best use of the 3P ammo. The fully-automatic, computerised loading system in the gun can handle 120 ready-to-fire rounds. The loading system is divided into two sections to enable instant switching between ammo types. For ease of integration, the length of the ammunition hoists can be adapted to the size of the ship. The only utility required is the power supply. Total system weight including 1,000 rounds is around 14,000 kg.