Manufactured by OTO-Melara, these weapons have a higher rate of fire and a greater maximum elevation than their rough equivalent, the USA 5"/54 (12.7 cm) Mark 45. Both use USN standard semi-fixed ammunition including surface, air, pyrotechnic and chaff rounds. Mounting reaction time is five seconds from target designation. The reloading, feeding and firing sequence is controlled by a central console which is operated by a single crewmember.
The Compact is intended for use on frigate and destroyer type warships. This mounting uses a water-cooled barrel mounted in a water-tight fiberglass gunhouse and has 66 ready-to-fire rounds in three drums located just below the gun house. Each drum can hold a different ammunition type and each can be independently selected. A central elevator hoists the ammunition and delivers it to two oscillating arms which move the rounds into the loading trays. The drums are automatically reloaded via two hoists which are manually loaded in the lower magazine. Reloading can take place while the gun is firing. As an option, this mounting can be fitted with a stabilized line of sight local control system.
The LW (for "Light Weight") is a simpler version intended for smaller ships such as corvettes. This mounting uses selectable dual ammunition feed and modular magazines with a minimum of twenty ready rounds. Three modular automatic feeding magazines are used, one for propelling charges and two for projectiles. This permits this mounting to fire two different and immediately selectable types of ammunition. The magazines can be reloaded while the gun is firing. Projectiles and propelling charges are hoisted separately to the gun level from below-deck feeding magazines. There is a composition station below the gun where the next round to be fired is selected just before it is taken up by the gun automatic loading system.
Both mountings use a water-cooled barrel, normally using sea water, but requiring fresh water for flushing after firing.
An interesting new munition for these guns is being developed by OTO-Melara. Called "Vulcano," this is a fin-stabilized, sub-caliber, extended range projectile which does not use rocket boost. Additional details are available in the ammunition section on the 127 mm/64 datapage.
| Designation | 127 mm/54 (5") Compact 127 mm/54 (5") LW |
|---|---|
| Ship Class Used On | Compact:
|
| Date Of Design | About 1965 |
| Date In Service | Compact: 1968 LW: 1985 |
| Gun Weight | N/A |
| Gun Length oa | N/A |
| Bore Length | 270.0 in (6.858 m) |
| Rifling Length | N/A |
| Grooves | N/A |
| Lands | N/A |
| Twist | N/A |
| Chamber Volume | N/A |
| Rate Of Fire | Compact: 40 rounds per minute LW: 40 rounds per minute |
| Type | Separate |
|---|---|
| Projectile Types and Weights 1 | Mark 80 HE-PD 2: 67.6 lbs. (30.7 kg) Mark 91 Illum-MT 2: 63.9 lbs. (29.0 kg) Mark 116 HE-VT 2: 69.7 lbs. (31.6 kg) Mark 127 HE-CVT 2: 68.6 lbs. (31.1 kg) Mark 156 HE-IR 2: 69.0 lbs. (31.3 kg) |
| Bursting Charge | N/A |
| Projectile Length | Mark 80: 26 in (66 cm) Mark 91: 26.1 in (66.3 cm) Mark 116: 26 in (66 cm) Mark 127: 26 in (66 cm) Mark 156: 26 in (66 cm) |
| Propellant Charge | Mark 67: 18.25 lbs. (8.3 kg) Cartridge weighs 38.9 lbs. (17.6 kg) filled |
| Muzzle Velocity | 2,650 fps (808 mps) Mark 91, only: 2,700 fps (823 mps) |
| Working Pressure | 18.5 tons/in2 (2,758 kg/cm2) |
| Approximate Barrel Life | 7,000 rounds |
| Ammunition stowage per gun | Compact ready-use: 66 rounds LW ready-use: 20 to 40 rounds Magazine: About 500 - 600 rounds |
All projectiles have a 0.5 caliber boat-tail. See also the 127 mm/64 for the Vulcano round.
1 This weapon can use USN standard 5"/54 (12.7 cm) ammunition. The ones listed above are meant to be representational but by no means is this a complete listing.
2 HE-PD: High Explosive, Point Detonating Fuze; Illum-MT: Illumination, Mechanical Time Fuze; HE-VT: High Explosive, Variable Time Fuze; HE-CVT: High Explosive, Controlled Variable Time Fuze.
| Elevation | With most Projectiles using Mark 67 cartridge |
|---|---|
| Range @ 47 degrees | 25,290 yards (23,130 m) |
| Effective Range | 16,400 yards (15,000 m) |
| AA Range @ 83 degrees | 23,000 feet (7,000 m) |
| Illumination | 18,085 yards (16,540 m) |
Illumination rounds are automatically timed to ignite at an altitude of 1,050 feet (320 m) over the target area.
| Designation | Single Mountings Compact LW |
|---|---|
| Weight | Compact: 82,670 lbs. (37,500 kg) LW: 48,500 lbs. (22,000 kg) |
| Elevation | Compact: -15 / +83 degrees LW: -15 / +70 degrees |
| Elevation Rate | Compact:
|
| Train | Compact: +165 / -165 degrees LW: +180 / -180 degrees |
| Train Rate | Compact:
|
| Gun recoil | N/A |
The Compact uses electric servos for training and elevation, and requires 440V, 3-phase, 60 Hz (275 kVA +20% max. peak power for 0.4 sec). Reloading of the loader drums is performed by 4 to 8 handlers in the ship's ammunition magazine. Drums can be reloaded while the gun is firing. Ammunition flow is reversible so that rounds can be automatically unloaded.
The LW uses hydraulically operated feeding and loading systems. Servo systems are electric with plug-in modular electronics. This mounting requires 440V, 3-phase, 60 Hz <180 kVA for the main circuit and 115V, 1-phase, 400 Hz, 300 VA, for the servo and synchro network. Drums can be reloaded while the gun is firing. Ammunition flow is reversible so that rounds can be automatically unloaded.
Data from:
- "Jane's Pocket Book 9: Naval Armament" edited by Denis Archer
- "The Naval Institute Guide to World Naval Weapon Systems 1991/92" and "1994 Update" both by Norman Friedman
- "The US Navy's Mk 45 Gun" article by Antony Preston in "Warship Volume VII"
Press releases:
NAVSEA 5-inch Gun Ammunition Fact Sheets
Special help by Leo Fischer
17 April 2008 - Benchmark
18 March 2009 - Added link to 127 mm/64 for Vulcano information
14 December 2012 - Added photograph of front view of LW mounting