5 in/54 naval gun ammunition 5 in/54 Calibre Projectile, Common 5 in/54 High Explosive/Controlled Variable Time HE-CVT

was developed during the last years of the Second World War but it was not a success, compared to the development of the Mk 18 gun on the various Mk 42 mountings. In 1971, these were followed by the Mk 19 gun on the Mk 45 series of mountings for the US Navy, now in widespread service (the US Navy has over 150 currently in service) and still the basis of further development. Mk 45 guns are in service with Australia, Greece , New Zealand, Thailand and Turkey , as well as with the US Navy. Metal parts for 5 in/54 calibre projectiles are manufactured at the Scranton Army Ammunition Plant operated by Chamberlain Manufacturing. The 5 in/Mk 45 Ultra-Lightweight naval gun was the subject of a May 1994 licence agreement between Royal Ordnance, UK (now BAE Systems , RO Defence) and Lockheed Martin, USA. The agreement, which involves manufacturing the system on a 50:50 basis, is with a view to RO Defence being the naval gun system prime contractor for the UK, French and Italian tripartite Common Next Generation Frigate (CNGF) programme (now cancelled). An adjunct to this agreement was that RO Defence and Alenia Difesa Divisione Otobreda of Italy are jointly engaged in developing a 5 in/127 mm ERHE round with a planned maximum range of 30,000 m. Available details of this round are provided below in this entry. A US Navy programme involves modifications to the Mk 45 mountings to provide for, among other objectives, a capability to produce a range increase of approximately 50 per cent for ballistic projectiles. In mid-1997, Lockheed Martin delivered a modified Mk 45 gun proof-of-concept firing assembly to the US Naval Surface Weapons Center in Virginia. This has a 62 calibre Mk 45 Mod 4 barrel and housing and a strengthened breech to accommodate the increase in muzzle energy from the current 10 MJ to about 18 MJ. By 1999, two full prototypes were to be delivered, with an introduction into service on DDG-51 destroyers during the year 2000. Between 18 and 28 mountings will initially be involved, with the longer term possibility of retrofitting about 150 existing guns still in service with the US and other navies. Further range increases for ship-to-shore bombardment will be obtained by the introduction of rocket assistance or gliding projectiles. The latter will provide Naval Surface Fire Support (NSFS) capable of attacking targets within 63 n miles (116 km) of a ship. As a first step rocket-assisted projectiles are being developed to extend ranges past the existing maximums. Another objective is to develop an Extended Range Guided Munition (ERGM) which will involve the use of Global Positioning System (GPS) and inertial navigation guidance trajectory control over 140 km plus ranges. In-service date could be as early as FY01. Maximum unit cost for production ERGMs is required to be no more than US$20,000 or lower. A GPS receiver suitable for use in a rocket-assisted 5 in (127 mm) projectile has been produced by the Interstate Electronics Corporation (IEC) of Anaheim, California. As an indication of what the ERGM could involve, Raytheon TI Systems, Inc, (formerly Texas Instruments) in association with the US Naval Surface Warfare Center, Dahlgren Division, is developing the EX 171 ERGM carrying 72 EX-1 submunitions (adapted from the US Army's XM80) each with a XM234 self-destruct fuze. The EX 171 is 1.55 m long and weighs 50 kg. Guidance involving GPS, locking onto four or more GPS satellites and with a back-up inertial navigation system (INS), is effected using canard fins while a rocket-assist motor burns for 15 seconds; this motor has been relocated from the tail to a position closer towards the nose. The submunition payload is ejected 250 to 400 m above a target area. Accuracy is claimed to be a 20 m CEP. Operational testing at sea was scheduled for FY01 although during testing some difficulties were encountered due to the high firing energies generated when firing the ERGM from the L/62 barrel mounted on the United Defense Mark 45 Mod 4 mounting. The energy level produced when firing the ERGM is of the order of 18 MJ compared to the 9.6 MJ produced firing conventional projectiles. This has resulted in the programmme being extended to FY04, although the US Navy hopes that it will be completed by the year 2003. A 155 mm version of the ERGM has been proposed for US Army deployment. Much of the guidance, navigation, control and payload technology involved in the 127 mm ERGM is shared with the 155 mm XM982 (which see). The US Navy is interested in developing a 155 mm naval gun to arm future generations of warships. This will provide ammunition commonality with land artillery systems and allow the Navy to make use of advanced and long range smart munitions formerly developed for land use. Description As with the earlier 5 in (127 mm) 38 calibre rounds, 5 in/54 calibre ammunition is semi-fixed. Compared with the earlier 5 in/38 calibre ammunition the rounds are longer with a more modern design, making the provision for deep intrusion fuzes. The forged steel projectiles are also longer and have a more streamlined outline, especially with the ogive, together with a distinct boat tail and flat base. The single wide copper drive band is retained. As with the 38 calibre ammunition, most of the projectiles are similar in weight (between 31 and 31.75 kg) and outward appearance, but all use a common charge system contained in a straight-sided 72:28 brass cartridge case which is 834.5 mm long. The usual operational charge is Full Charge (STD) but a Reduced Charge (RCHG) is also provided. All the case types mentioned below are basically similar and use loose-filled single-base multiperforated (seven-hole) diphenylamine powder propellants with an SPDF-type stabiliser and anti-flash additive, all held in place by a wad surmounted by a distance-piece. A case plug closes off the mouth of the case until just before loading. Primers are electrical. The types of cartridge case and their fillings (weights are nominal) are shown in the following text. Full Charge (STD) - Case Mark number 6 containing 8.4 kg of SPDN-BF or SPDF-BF propellant; Primer Mark number 13 Full Charge (STD) - Case Mark numbers 7 and 9 containing 8.4 kg of SPDN-BF or SPDF-BF propellant; Primer Mark number 45 Full Charge (STD) - Case Mark number 9 containing 8.4 kg of Universal propellant; Primer Mark number 45 Reduced Charge (RCHG) - Case Mark number 9 containing 2.85 kg of SPDF-BF propellant; Primer Mark number 153. As a range table guide, the muzzle velocity for Full Charge when firing a nominal 31.8 kg projectile is 808 m/s. Maximum range against surface targets when fired from a Mk 19 gun in a Mk 45 mounting is 23,600 m, while for air defence the maximum ceiling is 15,000 m. The Reduced Charge produces a muzzle velocity of 457.2 m/s with the same weight of projectile. The types of 5 in 54 calibre projectile are as follows: 5 in/54 Calibre Projectile, Common Although intended for use primarily against naval or other surface targets this projectile can be used as an anti-aircraft projectile; it approximates to the APC-T land equivalent. There is only one type, the Mk 42. It uses a forged steel body with an armour-piercing tip hooded behind a light-alloy streamlined ballistic cap. The centre of the penetrator body contains a 970 g Explosive D (ammonium picrate) burster charge. The base of the projectile has a base plug into which is threaded a base-detonating fuze which is intended to function only after the projectile has penetrated the target armour. To provide an impact marker for spotting purposes the hollow interior of the ballistic cap contains a marker dye container. Available dye colours are orange, red, blue and green. This projectile is normally fired using the Full Charge only. The nominal muzzle velocity is then 808 m/s. Projectile weight is 31.8 kg and length 665 mm. 5 in/54 High Explosive Projectiles There are numerous variants of the basic 5 in/54 calibre high-explosive projectile, which are essentially the same, yet, vary according to the size and presence or absence of a cavity in the base for a base fuze or the type of steel (fragmentation or non-fragmentation) used for the body. All body types have the same basic outline, are 660.4 mm long and have a nominal weight of 31.8 kg. These projectiles may use either Full or Reduced Charges. As a general guide, base detonating projectiles are filled with Explosive D (ammonium picrate) while point detonating projectiles use Composition A-3 (RDX/Wax 91/9). A new high-fragmentation HE projectile is a component of the Mk 45 Gun System Modification Program. 5 in/54 Anti-Aircraft/Controlled Variable Time - AAC This uses a mechanical time fuze fitted to the nose (normally protected before loading by a domed cover), along with an auxiliary detonating fuze located in a cavity behind the nose fuze and a base detonating fuze. The AAC body types likely to be encountered are the Mk 41 and 61, both of which contain 3.45 kg of Explosive D (ammonium picrate). 5 in/54 HE Also referred to as HC, this is essentially the same as the AAC but uses a point-detonating fuze in place of the mechanical time nose fuze. The body types involved are the Mk 41 and 61, both containing 3.54 kg of Composition A-3 (RDX/Wax 91/9). 5 in/54 High Explosive/Point Detonating HE-PD This is basically similar to the HE but lacks the base-detonating fuze. Where appropriate the base fuze cavity is closed by a threaded plug. The body types involved are the Mk 41, 55, 61 and 64, all containing 3.54 kg of Composition A-3 (RDX/Wax 91/9). 5 in/54 High Explosive/Variable Time HE-VT This projectile uses a radio proximity fuze which may or may not have a self-destruct element. With this projectile the base fuze cavity is plugged. Body types likely to be encountered are the Mk 41 and Mk 64, both containing 3.54 kg of Composition A-3 (RDX/Wax 91/9). 5 in/54 High Explosive/Controlled Variable Time HE-CVT This is fitted with a radio proximity fuze only (an infra-red proximity fuze was used at one time but was withdrawn) with fuze control effected through the use of a built-in mechanical timer. The body types likely to be used are the Mk 55, Mk 64 or Mk 65 high fragmentation, all with solid bases. All contain 3.54 kg of Composition A-3 (RDX/Wax 91/9). The French TDA 127 MM proximity fuze is one optional fuze for this projectile. A rocket-assisted HE projectile was developed for the 5 in/54, with a maximum range of 29,170 m at an angle of barrel elevation of 60º. It was not issued for service. 127 mm/5 in/54 ERHE This round is currently at the technology demonstrator stage to illustrate that a 30,000 m range can be achieved in support of the gun options being considered for the Common Next Generation Frigate (CNGF). Royal Ordnance and Alenia Difesa Divisione Otobreda are jointly engaged in the programme. The round is semi-fixed and of similar dimensions to the Mk 64 body and Mk 9 case combination from the 5 in/54 family to ensure compatibility with existing ammunition handling systems. The required range increase is provided by a 9.5 kg triple-base propellant charge to increase muzzle velocity to 910 m/s, and a Base Bleed (BB) unit. The projectile contains a nominal 3.5 kg of Composition A-3 (similar to that of the Mk 64) and has a forged steel body with improved fragmentation performance. Other available details are that the projectile weighs 28.6 kg, of which 2.12 kg is the fuze. Projectile length is 663 mm. 5 in MK 172, HE-ICM The US Navy Conventional Ammunition Program Office has completed qualification of a 5 in HE-ICM projectile for land attack and anti-submarine warfare. The projectile is based around the MK 172 projectile body capable of carrying a variety of payloads, including HE, Smoke, decoys and others, but for the HE-ICM role it carries 49 dual-purpose (fragments and shaped charge) MK 2 submunitions arranged in seven layers. The MK 2 submunition differs from the US Army's M80 in having the usual Comp A5 explosive charge replaced by PBXW-11/PBXN-5 insensitive explosives. As part of a future update programme the submunition M223 fuze will be replaced by the M234 with a self-destruct element. The expulsion charge is WC294 Ball Powder propellant. For the HE-ICM fuze, the existing MK 419 Multi-Function Fuze (MFF) has been modified by replacing the usual PBXN-5 booster with a transfer tube that ignites the expulsion charge. The modified fuze is known as the MK 429 MFF although it will be employed in the electronic time mode only. The base 5 in MK 172 HE-ICM has a baseline range of 13 nm, although it is planned to increase this to 21 nm once the EX 174 propelling charge has been qualified for the 5 in, 62 Caliber, MK 45 MOD 4 gun. Provisional approval for production for the baseline projectile body without fuze was given in March 1998. Limited production has commenced . 5 in/54 Calibre Projectile, Illuminating This is a conventional illuminating round. There is only one body type, the Mk 48-1, carrying the Mk 11 illuminating load which weighs 7.39 kg and produces 600,000 candlepower for 50 seconds. When the nose-mounted Mk 342-1 mechanical time fuze functions, the illuminating load is ejected from the projectile base by a 77.8 g black powder charge located behind the nose-mounted mechanical time fuze. The illuminating load (which uses 1.355 kg of powdered magnesium mixed with an oxidiser) then descends suspended from a 940 mm parachute. The projectile weighs 30.93 kg and is 662.4 mm long. Full or Reduced Charges can be used. 5 in/54 Calibre Projectile, Chaff Chaff projectiles are used as a basic Electronic CounterMeasure (ECM) by filling a volume of air with a large number of small metallised glass fibre needles, these produce a large radar cross-section to confuse enemy radars or missiles. The projectile uses a Type B (S-band), Type C (X-band) or Mk 22 Mod 0 (S-band) chaff load in a body interior optimised in volume to accommodate chaff payloads, it also uses a mechanical time fuze. Payloads are ejected through the projectile base by a small ejection charge located behind the nose-mounted fuze. A typical 5 in/54 Chaff projectile weighs 31.4 kg and is 662 mm long. Maximum range using the Full Charge is 21,860 m. Full or Reduced Charges can be used. This projectile is no longer in the US Navy inventory. 5 in/54 White Phosphorus (Smoke)/Point Detonating WPW/PDF This projectile uses an unusual smoke production system, in that a Mk 14 canister containing White Phosphorus (WP), is ejected from the base of the carrier projectile once the nose-mounted Mk 89 point-detonating (over land) or Mk 90 mechanical time (over sea) fuze has functioned. The canister, which is 384.3 mm long, is ejected by the internal pressures created by a 56.7 g expulsion charge located beneath the nose fuze cavity. The same charge also initiates a delay element in the top of the canister. After the delay is complete the delay element detonates a burster tube running through the centre of the canister and breaks the canister open to disperse the white phosphorus. This then creates a grey/white screening smoke cloud which, in still air conditions, persists for up to 7 minutes and is approximately 45 m in diameter. The WP with this projectile is coated with synthetic rubber to improve its shelf life - the coated product is called TWP (plastizised White Phosphorus). The projectile weighs 31.75 kg and is 661.9 mm long. Full or Reduced Charges can be used. As a general guide a complete 5 in/54 calibre round weighs 47.9 kg. 5 in/54 Practice projectiles with inert fillings and dummy fuzes have also been produced along with completely inert handling training and `ramming' rounds. 5 in/54 TP rounds include the Target Practice (PUFF)/Mechanical Time (TP/PUFF) and the Target Practice, Non-fragmenting/Variable Time (VT/NONFRAG). Authorised fuzes Several types - see text Equivalent rounds ITALY ITALY Manufacturer Simmel Difesa SpA Type: HE, ILL, FNF, BL Description: FNF is Flash No Frag for training and spotting while BL is Practice. Charges and various types of fuze, including Proximity, also available. Weight of all projectiles given as 32 kg and propellant charge weight 7 kg SPAIN Manufacturer DEFEX SA Type: HE-VT, HE-MT, E (Prac) Description: Standard US specifications Manufacturer EXPAL SA Type: HE-VT, HE-MT, VT-NF, E (Prac) Description: Standard US specifications