Barrack Buster - Provisional IRA's Improvised Mortars

Provisional IRA's Improvised Mortars

The barrack buster belongs to a series of home-made mortars developed since the 1970s. The first such mortar—Mark 1—was used in an attack in May 1972 and it was soon followed by the first of a series of improved or differentiated versions stretching into the 1990s:

• Mark 1 (1972): consisted of a 50 mm copper pipe filled with 10 ounces (0.26 kg) of plastic explosives. Propelled and detonated by two commercial low-caliber cartridges.
• Mark 2 (1972–73): an 8 in length 57 mm steel pipe filled with two pounds (0.9 kg) of explosive and detonated by a 12 gauge shotgun cartridge. This weapon resulted in the first fatality due to PIRA mortars when a British soldier was killed trying to defuse a misfired projectile launched on Fort Monagh barracks at Turf Lodge, Belfast, on 10 December 1972.
• Mark 3 (1973–74): a 60 mm mortar barrel with a static firing pin on the plate and a range of 260 yards (237 m). Propelled by a dried mixture of rags and sodium chlorate and detonated by a charge of ammonium nitrate. Used in attacks on Creggan Camp, Derry and Lisanelly barracks, Omagh, in 1973. During an attack on a police station a misfired mortar killed two IRA men (aged 16 and 27) operating the mortar.
• Mark 4 (1974): Basically a Mark 3 with a larger charge of propellant which extended its range to 400 yards (365 m). The bomb was filled with 1 pound (0.45 kg) of ammonium nitrate and aluminium powder. Used only in one known attack on a base in Strabane, County Tyrone, on 22 February 1974.
• Mark 5 (1974): Never used in any known attack, the security forces learned of it after the discovery of an IRA workshop at Cushendall, Antrim, in 1974.
• Mark 6 (1974–94): A 60 mm conventional mortar with a bipod and base plate and a range of 1,200 yards (1,097 m). The shell was propelled by a charge of homemade gun powder, ignited by a .22 cartridge. The warhead, made of 3 pounds of Semtex, was detonated by another .22 cartridge on impact. The bomb armed itself "by means of a wind-driven propeller, which is an integral part of the striker". A Mark 6 grenade was thrown by hand on the roof of an armored vehicle from the top of Divis Flats, Belfast, causing widespread damage and some casualties. It was used in March 1994 in three attacks on Heathrow airport in Britain. It is not known to have been used after these attacks.
• Mark 7 (1976): Longer version of Mark 6.
• Mark 8 (1976): Longer version of Mark 6.
• Mark 9 (1976–?)
• Mark 10 (1979–94): A large caliber mortar containing 44–220 pounds (20–100 kg) explosives. Its first use on 19 March 1979 caused the first deliberate victim—a British soldier—from an IRA mortar attack in Newtownhamilton, South Armagh. It was primarily designed for use against police stations and military bases, and was used in the 1985 Newry mortar attack which killed nine Police Officers. It was used in several attacks using configurations with multiple launching tubes, "often launched from the back of Transit type vans". Three such mortars using a mixture of ammonium nitrate and nitrobenzene—known as "Annie"—as warhead were used on 7 February 1991 in an IRA attack on 10 Downing Street in London against British Prime Minister John Major and his War Cabinet during the first Gulf War. It was superseded by the larger Mark 15.
• Mark 11 (1982–?) : Used for the first time on 13 May 1989 against a British Army observation post in Glassdrumman, South Armagh. The mortar had a range of 550 yards (519 m).
• Mark 12 (1985–?): Fired horizontally against armoured vehicles as well as RUC/Army bases. Also referred to as Improvised Projected Grenade. With a warhead made of 40 ounces (1.1 kg) of Semtex and TNT. Used successfully in 1991 and 1992.
• Mark 13 (1990–?): A spigot mortar, usually lobbed to the intended target from the back of a heavy vehicle.
• Mark 14 (1992–?)
• Mark 15 (1992–?): First mortar known as "barrack buster". It is the "standard IRA large calibre system" and described as having "the effect of a 'flying car bomb'". It has a calibre of 320 mm and loads with 196–220 pounds (80–100 kg) explosives and a maximum range of 275 yards (250 m). It has also been used in configurations with multiple launch tubes with an attack using 12 tubes against a British military base in Kilkeel, County Down, on 9 October 1993 as being the "record". Two British helicopters, one Lynx from the Army and an RAF Puma, were brought down by this type of mortar between March and July 1994 in South Armagh. Author Toby Harnden describes the 1994 shooting down of the Lynx as the most successful attack on a helicopter by the IRA during the Troubles. The barrel was usually attached to a hydraulic hoist towed by a tractor to the launching site.
• Mark 16 (1991–?): A shoulder fired weapon for use against armoured vehicles. Used successfully in eleven attacks from late 1993 to early 1994. Also described as Projected Recoilless Improvised Grenade. The projectile consisted of a shaped charge with armour piercing capabilities, made of a tin can of 1 pound (0.45 kg) filled with 600 grammes of Semtex.