30mm Oerlikon GCM-A


BMARC A32


Overview

30mm GCM-A03-2

Rear view of a Royal Navy 30mm GCM-A03-2 seen firing its 30mm KCB autocannon in 2005.
Source: Matzos - © Copyright lies with original owner

Origin
United Kingdom
Type
Naval gun
Entered service
Early 1970's for GCM-A01
1974 for GCM-A02
Early 1980's for GCM-A03
Status
In service
Development
1966 - 1971 (GCM-A01)
Early 1980's (GCM-A03)
Developer
United Kingdom - BMARC (mount)
Switzerland - Oerlikon (autocannon)
Production
1970's (GCM-A01 and A02)
Early 1980's - 2000's (GCM-A03)
Producer
United Kingdom - BMARC (mount)
Switzerland - Oerlikon (autocannon)
Number produced
Over 100 mounts
Designations
A32 (early name for mount)
Notable users
United Kingdom
Egypt
Sri Lanka
Kenya

Description

Introduction

The GCM-A is a late Cold War gun mount of UK origin. The mount was developed by the British Manufacture and Research Company (BMARC) which called it the A32 using Hispano-Suiza HS.831 autocannon. When acquired by Oerlikon these autocannon were renamed the Oerlikon KCB and the mount was marketed as the GCM-A.

Design

The GCM-A01 is armed with two Oerlikon KCB autocannon firing a range of ballistically matched ammunition. The GCM-A03 is the second generation of GCM-A twin gun mounts. The mount has been redesigned to improve its efficacy. This was achieved using a more capable gyro-stabilized gun sight and the addition of remote fire control. The mount is electrically powered with hydraulic powered traverse and elevation. The mount is available with enclosed cabin, open cabin and no cabin with remote control only.

Firepower

The GCM-A is fitted with two Oerlikon KCB autocannon. These are single belt-fed. Mostly with 250 round belt per gun, although options for 160 and . These may feature a mix of ammunition types. Cyclic rate of fire is 650 rpm per barrel and 1.300 rpm combined. Effective range is about 2.5 km against aircraft and 3 km against surface targets.

Users

The GCM-A01 and A02 were exported to various nations for use on patrol boats and fast attack craft. Egypt and Kenya are the main users of the first generation systems. The GCM-A03 was acquired by a number of nations for use on patrol boats and fast attack craft. These include Jordan, Sri Lanka and Tunisia. The UK acquired the GCM-A03 for use on the Type 22 frigates, Type 42 destroyers and some auxiliary vessels. In Batch 3 of the Type 22 it was replaced by 30mm Goalkeeper close-in weapon system.

Variants

30mm GCM-A03-2

A 30mm GCM-A03-2 seen on a Royal Navy Type 22 frigate.
Source: Royal Navy - © Crown copyright

List of variants

GCM-A01
First generation open gun mount. Fitted with basic reflector sight. Introduced in the early 1970's.
GCM-A02
First generation enclosed gun mount. Fitted with the same basic reflector sight. Entered service in 1974 with Kenya.
GCM-A03-1
Updated GCM-A02 with enclosed cabin. Has either 165 or 250 rounds per gun on mount. Fitted with a GSA Mk 201 gyro-stabilized sight for much improved accuracy with local control.
GCM-A03-2
Updated version of the GCM-A01 with open cabin. Local and remote control with 250 rounds per gun on mount. Fitted with a GSA Mk 201 gyro-stabilized sight for much improved accuracy with local control.
GCM-A03-3
Remote control only variant offered in the 1980's. Largest ammunition capacity on mount with 320 rounds per gun.

Details

Facts GCM-A03-1 GCM-A03-2 GCM-A03-3 GCM-A01
General
Origin
Switzerland / United Kingdom
Type
Naval gun
Ordnance
Type
2x 30mm Oerlikon KCB
Rate of fire
650 rpm cyclic per barrel
1.300 rpm combined
Range
3 km against surface targets
2.5 km against aircraft
Muzzle velocity
1.080 m/s
Barrel life
5.000 rounds
Mount
Feed mechanism
Single belt feed per autocannon
Ammunition
320 or 500 rounds on mount, 160 or 250 per gun
Traverse
360°, powered
Traverse rate
85°/s
Elevation
-13° to +75°, powered
Elevation rate
60°/s
Operation
Crew
1 on mount
Cabin
Enclosed, optional air conditioning system
Fire control
GSA Mk 201 gyro-stabilized gun sight for local control
Remote control
Dimensions
Weight
2.15 t unloaded
Width
2.48 t with 320 rounds
2.74 t with 500 rounds
Swept radius
2.52 m
Length
3.66 m with short ammunition bins
3.96 m with large ammunition bins
Width
2.24 m
Height
1.88 m
Deck penetration
No, except for power cables and remote control inputs

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