The standard towed version of the M55 is designed for infantry use. The M55 consists of three
license-produced cannons (Hispano-Suiza HS.804 20 mm L/70) held in place on a single mount and a towed carriage for transportation.
Basic tactical and tehnical characteristics:
| Caliber | Lengt Transport Position | Weight Transport Combat | Effective Range | Maximum Range | Muzzle Velocity | Rate of Fire | Elevation Horizontal Field |
|---|
| 20 mm | 4,3 mm | 970 / 1150 kg | 1200 / 2000 m | 5500 / 4000 m | 835 – 880 m/s | 11 rds /s | -5° do +83° / 360° |
- Carriage clearance is 230-380 mm (depending on the model). Maximum speed on asphalt road is 70 km/h.
- Ammunition cal. 20×110 mm: M60 armour-piercing grenade pointer/marker, TZO M57 explosive torch cartridge and exercise grenade (M79 and M77)
- M55A2Bl : Weapon control is manual with two handrails. Gunner aims with optical-mechanical si ht PANS-20/3 and o ens fire with a edal.
- M55A3Bl : The hydraulic directional drive of the gun which is driven by a small gasoline engine «Wankel» to the ri ht of the unner’s seat. Gunner uses ·o stick for un control.
- M55A4B : Engine is placed under the gunner’s seat. New optical sight J-171 is installed. A s linter- roof shield is installed in front of the o ti cal si ht and the gunner,
- M55A4Ml : A modified A4 B 1 system upgraded with the Galileo J1 71 ballistic computer, mounted on a turret installed in the top roof of a BOV armoured personnel carrier.
- M71/08 : This version is installed on ships. Cannons and ammunition box (mounted beneath the the cannon bottom) are positioned so that the mount and the cartridge collector protect against water.
