This weapon system is a result of a collaboration between OTOBreda (now OTO-Melara) and Oerlikon Italiana. It is intended to replace older 20 mm Oerlikon weapons and fires much more powerful ammunition. The Power Assisted (PA) Naval Mounting for this weapon provides hydraulic power assistance such that the gunner needs only to apply as much force as it would take if the ship were not moving at all. The gunsight adjusts automatically so that the gunner can remain standing instead of crouching down when the gun is at high elevations.

The gun itself is an Oerlikon KBA which is belt fed with dual feed.

This weapon is also available in either a single, above deck mounting with local or remote control or in a Compact-style mounting with a below-deck magazine. These mountings are also shared with the 30 mm version.

Gun Characteristics

Designation 25 mm/80 (1") KBA Oerlikon
Ship Class Used On Coastal Patrol Boats
Date Of Design about 1987
Date In Service 1990
Gun Weight N/A
Gun Length oa N/A
Bore Length about 79 in (200 cm)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 570 +/-50 rounds per minute cyclic


Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights HEI-T: about 0.34 lbs. (0.16 kg)
APDST: about 0.34 lbs. (0.16 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Cartridge 25 x 137 mm
Muzzle Velocity HEI-T: 3,609 fps (1,100 mps)
APDST: 4,380 fps (1,335 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun Power Assisted Mounting: up to 252 rounds of ready ammunition
Others: N/A


Effective range with 0.34 lbs. (0.16 kg) HEI-T
2,200 yards (2,000 m)

Mount/Turret Data

Designation 25 mm Power Assisted (PA) 1
25 mm Compact Single or Twin 2
Weight Power Assisted - empty: 2,050 lbs. (930 kg)
Compact: N/A
Elevation Power Assisted: -15 / +50 degrees
Compact: -13 / +80 degrees
Elevation Rate Power Assisted: N/A
Compact: 75 degrees per second
Train 360 degrees
Train Rate Power Assisted: N/A
Compact: 130 degrees per second
Gun recoil N/A
  • ^The Power Assisted mounting was originally designed for two 80-round ammunition boxes. Later, 96-round boxes were designed and now a newer version can carry two 126-round boxes. A box with 96 rounds weighs 132.3 lbs. (60 kg). This mounting uses a 24 Vdc lead-acid battery which is recharged from the ship's power supply.
  • ^The twin Compact version uses a specially designed OTOBreda cradle. This can carry 2,000 rounds (Type A version), 1,000 rounds (Type B version) or 500 rounds (Type C version). The differences are mainly in the depth of the below-deck magazine.

Additional Pictures


Data from:

  • "The Naval Institute Guide to World Naval Weapon Systems 1991/92" by Norman Friedman
  • "Jane's Ammunition Handbook: Ninth Edition 2000-2001" edited by Terry J. Gander and Charles Q. Cutshaw

Press releases:


17 April 2008
26 May 2012
Updated to latest template