Mk 45 5-Inch 54-Caliber Naval Gun Mod 4

United Defense is developing the Mk 45 Mod 4 Naval Gun System to enhance US Navy capabilities for Naval Surface Fire Support (NSFS) and the variety of other gunfire missions for surface combatants. The 5-Inch (127-mm) 62-Caliber Mk 45 Mod 4 will deliver all-weather, day/night, over-the-horizon NSFS mission firepower, as well as fire mission flexibility for antisurface and antiair warfare. The Mk 45 Mod 4 Naval Gun System design also provides a new gun mount shield to reduce overall radar signature, maintenance, and production cost.

The Mk 45 Mod 4 Naval Gun System will provide an NSFS range of over 60 nautical miles with the use of Extended Range Guided Munitions (ERGM) and structural modifications to the basic Mk 45 Gun Mount. These modifications include a 62-caliber barrel, strengthened trunnion supports, lengthened recoil stroke, an ERGM initialization interface, round identification capability, and an enhanced control system. This low-risk approach minimizes impact on the proven-reliable system design and for its application to current and future surface combatants.

The Mk 45 Mod 4 Naval Gun System’s ability to selectively handle and fire all types of US Navy 5-inch ammunition provides a high degree of mission flexibility across a wide spectrum of naval gunfire missions. If necessary, a single crew member can activate and operate the entire system.

The Mk 45 Mod 4 Naval Gun System is being forward-fitted to US Navy DDG 51-Class destroyers beginning in the year 2001. Mk 45 Mod 4 Naval Gun System design enhancements can also be backfit through Ordnance Alteration (ORDALT) retrofits to over 120 Mk 45 Mods 0 through 2 Naval Gun Systems already in service with the US Navy and international naval forces. United Defense provides complete integrated logistics support for the Mk 45 Naval Gun System that is keyed to customer requirements and backed by the worldwide logistics system supporting the US Navy.