It is a positively locked breech, gas and recoil operated cannon with a rotating bolt head and a dual-belt selective feed system taking a 25mm NATO cartridge.

The Oerlikon KBA 25 mm is a fully automatic cannon based on the proven gas-operation principle with a rotating bolt head similar to the Mauser M 98 or M16 and double belt feed for the ammunition.

The cannon functions, such as cocking and firing, are electrically actuated by a remote control unit or manually in auxiliary mode by means of a hand crank and a trigger pedal.

At the turn of 1964-65, the US Army started the ambitious Bushmaster project as an offshoot of the MICV-65 program to replace the M113 armored personnel carrier with a new infantry fighting vehicle.

[4] TRW's requirements for the 25mm project were that the gun had to be fully automatic and actively locked, be operated by gas and with a rotating bolt head, and use a dual-belt selective feed system allowing a quick and easy switch between different ammunition types.

In the meantime the Swiss Oerlikon-Bürle factory obtained from TRW the license of the TRW-6425 for Europe in 1967[7] and they started the "KBA series" 25mm cannon project based on it.

Oerlikon devoted huge development efforts to improve the functional reliability, durability and firing precision of the KBA autocannon.

The current 25x137mm ammunition family consists in different combat (air - ground) and training rounds types as follow: These are the characteristics of the best-known KBA autocannon weapons stations in use and presently in production: VALHALLA MANGART 25 is a remote controlled SHORAD / multifunctional turret, designed for integration with modern wheeled or tracked armoured fighting vehicles.

[16] The MANGART 25 turret is designed to mount a 25mm Rheinmetall KBA (25x137mm) autocannon paired with a high performance electro–optic system (cooled and un-cooled) and a co-axial machine gun provides fire support for the main cannon.

[17] The Aselsan NEFER-L is a remote controlled weapon station (RCWS) can be mounted on 4x4, 6x6 and 8x8 wheeled or tracked vehicles and is developed primarily for use against armored land targets.

OTO Melara has also developed the OTO SINGLE 25mm KBA[20] as a stabilized, electric servo-drive assisted weapon station, for naval applications with 252 ready-to-fire rounds made to neutralize targets in the Anti Surface Warfare, particularly in the Asymmetric Warfare or Mine Defence scenarios and thanks to the high rate of fire of the 25mm KBA cannon also offers a capability in very close Anti Air Defense.