The Indian Navy is adopting the U.S. Navy Mk 45 127mm (5 inch) gun for its latest destroyers and frigates. In the past India had used Italian 76mm guns or Russian 100mm guns. Initially India is spending $560 million for eleven Mk 45 Mod 4 127mm gun systems. The U.S. us supplying three Mk 45s immediately by taking them from the U.S. Navy inventory, which will get those replaced as the eleven Mk 45s for India are built.
Designed by United Defense, an American firm bought by BAE in 2005, the Mk 45 continues to be built in the United States. Each Mk 45 system weighs 22 tons, including turret and ammunition delivery system. The Mk 45 is remotely controlled by the ship fire control system. The turret is unmanned and uses an automatic loader so that up to 20 shells a minute can be fired. Rarely is this high rate-of-fire mode used anymore because it was originally needed for air defense using shells with proximity fuzes that exploded when near an aircraft.
The U.S. Navy also spent over $600 million developing a GPS guided 127mm shell but abandoned the first effort in 2008 and started another search in 2014 because more recent GPS guided shells seemed to work effectively enough to justify adopting it. The new GPS guided shell would be used to fire shells that detonate above swarms of small boats and destroy or disable these fast-moving boats with shell fragments. The Mk 45 has become a popular armament for other navies and is currently exported to ten countries with Canada, India and Britain joining the list.
In the 1930s the 127mm gun became standard armament for U.S. warships, mainly destroyers, when the Mk 12 was introduced and used until the 1950s when replaced by the Mk 42. In 1971 the current Mk 45 was introduced and has undergone many upgrades to remain in use. There was a major Mk 45 upgrade in 2000 when the 54 caliber long 6.9-meter (22.5 foot) barrel was replaced by the 60-caliber 7.9-meter (25.8 foot) Mod 4. All the earlier mods used the shorter barrel, which could fire a shell out to 24 kilometers. The longer barrel can fire out to 37 kilometers. The 60-caliber barrel wears out after firing about 7,000 shells. American destroyers armed with the Mk 45 carry 680 127mm shells of various types. Most of the shells are HE (High Explosive) with detonation on contact or proximity fuzes. Illumination shells are common as well. These shells weight 30 to 32 kg each. The separate propellant charge weighs about 18 kg. Most 127mm shells have an initial velocity of 830 meters a second (2,700 feet per second) but some types of shells move at over a thousand meters a second. In effect the Mk 45 is a very large rifle and at one time warship designers called such naval guns “rifles”.
This latest Indian purchase of American weapons is part of a growing trend. India is replacing most of its Russia military equipment with more effective, and expensive, Western gear. Not just American, but from all the prominent European suppliers as well as Israel and South Korea. Israel was the first major exporter of modern military tech to India but the Americans have since caught up and surpassed Israel. Buying American is also something of an insurance policy as the U.S. tends to back its major customers diplomatically. Buying a lot of American military equipment makes it easier to develop more military links with the United States. During the Cold War it was popular in India to avoid cooperation with the United States while making Russia a major supplier of weapons. In hindsight that was a poor choice because it included admiration for communist policies, which crippled Indian economic development and growth. After all the European communist governments collapsed and went democratic by 1991, Indians realized they had to change. The economy thrived and the new Western military gear was clearly superior to the Russian stuff.