Oerlikon KBA

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Oerlikon KBA 25 mm
Oerlikon KBA.JPG
Oerlikon Contraves 25 mm automatic cannon Type KBA
Type Autocannon
Place of origin   Switzerland
Service history
In service Mid 1970's – present
Used by See operators
Production history
Designer Oerlikon Contraves AG
Manufacturer Rheinmetall Italia S.p.A;
Ford Motor Company (designated KBA-B02 under license agreement with Oerlikon and TRW Inc. as a competitor to Hughes' Bushmaster)[1]
No. built 10,500+
Weight 112 kilograms (247 lb)
Barrel length • Overall: 2,888 mm (113.7 in)
Width 263 mm (10.4 in)
Height 253 mm (10.0 in)

Shell NATO 25×137mm
Caliber 25 mm
Barrels Single barrel
Rate of fire • Nominal: 600 rounds/min • Maximum: 700 rounds/min
Muzzle velocity 1,335 metres per second (4,380 ft/s)
Effective firing range 3,020 metres (9,910 ft)
Maximum firing range 6,850 metres (22,470 ft)

The Oerlikon KBA is a 25 mm (25×137mm) cannon, developed as a close range weapon for the mechanized battlefield originally made by Oerlikon Contraves AG (renamed as Rheinmetall Air Defence AG following the merger with Rheinmetall in 2009).

The Oerlikon KBA is a gas operated selective fire weapon taking a 25 mm cartridge from a dual selective belt feed and firing at a rate of 600 rounds per minute, it has been developed as a close-range multipurpose weapon for the modern battlefield.

Due to its firepower, various types of ammunition and its Instant Ammunition Selection Device (IASD), the KBA can engage lightly armoured vehicles, infantry and antitank positions, helicopters, combat aircraft and ships.


The Oerlikon KBA 25 mm cannon is a fully automatic, positively locked, gas-operated weapon with a rotating bolt head and double belt feed. These features guarantee high reliability and safety, even under the most extreme environmental conditions.

The KBA offers a wide range of firing modes: single shot; programmable rapid single shot with a rate of fire of up to 200 rds/min; and full automatic fire of 600 rds/ min. The cannon functions, such as cocking and firing, are electrically actuated by remote control unit or in auxiliary mode mechanically by a hand crank and a trigger pedal.

The Oerlikon KBA 25mm cannon has been designed for integration in various types of mounts, small size and low weight offer various integration possibilities such as:

  • Manned (1 or 2 operators) or remote controlled turrets on IFVs, APCs
  • Air defence gun mounts
  • Naval mounts
  • Helicopter mounts

The various types of available ammunition combined with the unique Instant Ammunition Selection Device (IASD) and different selectable firing modes with a rate of fire up to 600rds/min support any type of operational use.


In 1964 the American company TRW Inc. was entrusted with the development of a 25 mm weapon while Oerlikon-Buehrle Machine Tool Works assumed responsibility for developing the ammunition and interior ballistics for it.

Both were intended to meet the requirements for the armament of infantry fighting vehicles of the 80's and 90's like:

  • Ammunition performance 25 mm armour steel, 60° (NATO) angle of impact, 1000m range, corresponding to the armour of a well armoured infantry fighting vehicle.
  • Instant ammunition selection for engagement of different targets
  • Selectable firing mode Accurate single shot, bursts with a rate of fire of more than 550 rds/min for engagement of aircraft
  • Compact structure with low weight for installation in gun turrets of APC's
  • Simple to operate and service in the hands of infantry

Three years later, at the beginning of 1967, technical tests and firing trials were carried out with the first two American prototype (recoil operated) cannons (TRW-6425)[2] at Oerlikon-Buehrle Machine Tool Works followed by the first demonstrations for another NATO country.

In the trials, however, the American prototypes displayed a number of basic functional deficiencies. This persuaded Oerlikon-Buehrle Machine Tool Works to undertake their own development work to effect system modifications, which then resulted in the required functional reliability and enabled the trials to be completed successfully. (1970, 10 gas-operated cannons). When the first prototype cannons became available, suitable gun turrets had also to be provided. In 1967 an agreement was signed between Machine Tool Works Oerlikon-Buehrle and a well-known and established sub-contractor, to collaborate in the development and manufacture of 25 mm gun turrets. These gun turrets were in the first instance to be suitable for mounting on armoured personnel carrier M 113 C&R of a NATO country's army. The complete system, cannon, hand-driven turret and ammunition underwent detailed firing trials between 1969 and 1971. Special new development efforts were devoted to improve functional reliability, durability and firing precision, and in 1971 sufficient progress had been made for the weapon system to fulfil the strict specifications laid down, and to be delivered to the Netherlands.

Within the framework of the product support service Oerlikon improves the product and adapts it regularly to the latest requirements. An important step forward was made in 1982/83 when the ammunition penetration performance range of the 25 mm APDS-T (sub-caliber) round was increased 150% from 1000 to 2500 m.

The wide range of strong points of the Oerlikon KBA 25 mm cannon, such as high rate of fire, ammunition performance, good safety record, dual belt feeder with first-round response, no external power requirement and simple maintenance lead to a considerably increasing interest in the Oerlikon KBA 25 mm cannon in years.


A wide range of ammunition has been developed for this weapon specifically developed to engage and defeat both ground and air targets.

The ammunition complies with all handling and operational safety requirements according to MIL-STD’s, and was subjected to intensive trials by NATO member countries prior to its introduction and standardization as NATO 25mmx137 ammunition.

US Navy Gunner's inspects rounds 25x137 TP-T

The current 25mm ammunition family consists of 6 prime war-shot and 2 training rounds:

  • APFSDS-T: armour-piercing fin stabilized discarding sabot with tracer, for use against armoured ground targets
  • APDS-T: armour-piercing discarding sabot with tracer, for use against armoured ground targets
  • FAPDS-T: frangible armour-piercing discarding sabot with tracer, for use against air, ground and urban targets
  • TPDS-T: target practice discarding sabot with tracer, a short range trainer for the above sub-calibre types
  • SAPHEI-T: semi-armour-piercing high explosive incendiary with tracer, for use against well protected targets
  • HEI-T: high explosive incendiary with tracer, for use against lightly protected targets
  • MP-T: multipurpose with tracer
  • TP-T: target practice with tracer, for training with the above full calibre types


Current operators

Example of KBA gun installed on Italian 8x8 Freccia wheeled Infantry fighting vehicle in use with the Italian Army.


  1. ^ Fiscal Year 1977 Authorization for Military Procurement, pt.6, p. 3268.
  2. ^ "Mm Trw Automatic Cannon - Machine Gun V5". www.bevfitchett.us. Retrieved 2017-03-30.
  3. ^ "Aselsan STOP 25mm Remote Weapon Stations for Pakistan Navy Fleet Tanker Project". Navy Recognition. Retrieved 2017-03-30.
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