30mm DS30M Mark 2 Automated Small Calibre Gun
The 30mm DS30M Mark 2 is a ship-protection system made by MSI Defence Systems consisting of a 30mm Mark 44 Bushmaster II cannon on an automated mount. It was designed to defend Royal Navy frigates from fast inshore attack craft armed with short-range missiles, rockets, rocket-propelled grenades, heavy machine guns or explosives. It replaced in this role the 30mm Oerlikon KCB gun on a DS30B manual mount. The DS30M has also been added to patrol boats and corvettes for the Iraqi and Omani navies respectively.
The DS30M Mark 2 system consists of a 30mm Mark 44 Bushmaster II on a fully automated mount with an off-mount electro-optical director (EOD). The gun and the EOD are controlled from a remote operator console elsewhere on the ship. The "mount is a single cannon naval mount that is gyro stabilized, electrically operated and self contained gun mounting featuring a choice of cannon, control mode and sights. It has low magnetic, radar and IR signatures and excellent ergonomic availability, reliability and maintainability (ARM)." In theory "the unique dual feed system of the Bushmaster series allows the operator to select different types of ammunition for use against a variety of targets. The safety, reliability and low life-cycle costs of the Bushmaster system added to its overall value." However photographs show only a single ammunition feed.
In August 2005, the Maritime Gunnery and Missile Systems Integrated Project Team in the UK Ministry of Defence awarded MSI-Defence Systems (part of MS International PLC) a contract "to supply a total of 26 ASCG systems for retrofit to the RN's 13 Type 23 frigates as part of the wider littoral Defensive Anti-Surface Warfare (ASuW) upgrade programme." This contract is worth more than £15 million (USD30.7 million) to MSI. The system is being bought because "Fleet Command and the UK Ministry of Defence's (MoD's) Directorate Equipment Capability (Above Water Effect) - DEC(AWE) - have identified a significant capability gap in the RN's ability to defend itself against fast attack craft and 'swarming' fast inshore attack craft threats in the littoral. The latter include powerboats, interceptors, rigid inflatables and jet-skis variously equipped with short-range missiles, rockets, rocket-propelled grenades, heavy machine guns or explosives."
MSI undertook land-based trials at Eskmeals in Cumbria. In mid-2007 MSI delivered the first two mountings, which were installed on HMS Somerset in August 2007, and used in sea trials on gun ranges in the English Channel in starting in early October 2007.
In 2008, a small analysis and management consultancy company CORDA (part of BAE Systems) was "awarded a £300,000 research contract by the UK MoD's Defence Technology and Innovation Centre (DTIC) to assess the level of protection British warships receive from small calibre 30mm guns." CORDA's programme manager said: "What we are doing is looking at the performance of the Royal Navy's 30mm Automated Small Calibre Gun (ASCG) [30mm DS30M] and what can be done to increase the level of protection it provides.'... 'The ASCG system has significantly enhanced capability, but we have been asked to look at how improving tactics or integrating further technology could improve the performance of the system further." The study used "simulator based operator trials and aims to quantify the performance of the entire weapon system when engaging multiple vehicles attacking together in a co-ordinated fashion. Results of the study are expected in early 2009." The trials were at the Maritime Warfare School at HMS Collingwood. CORDA worked in partnership with GE FANUC and BAE Systems' Advanced Technology Centre, in conjunction with the DE&S Integrated Project Teams (IPTs), with Dstl providing technical direction.
The system is being fitted to the Royal Navy's Type 23 frigates, starting with HMS Montrose. In January 2009 the ship began a six-month refit at Rosyth, in which it was fitted with the 30mm DS30M Automated Small Calibre Gun systems in place of its older manually operated 30mm DS30B.
The system is being fitted to newly indigenous built Krabi class offshore patrol vessel (Modified Port of Spain class corvette), Angthong class LPD (Modified Endurance class LPD), Naresuan class frigates (during MLU) , and Inshore patrol vessel T.991-T.996 
- Global Security Mk 44 Bushmaster II 30/40mm Automatic Cannon / Mk 46 Weapon Station.
- Scott, Richard, ASCG enhances Type 23 close-in defence, International Defence Review, 30 October 2007.
- New study to examine warship protection, CORDA news, 26 June 2008.
- HMS Montrose website, news dated 14 January 2009.
- Warship Technology, March 2009.
- Swiftships Orders Build Iraqi Navy’s Coastal Patrol Capabilities.