Oerlikon 35 mm twin cannon

Oerlikon GDF
A modernized Finnish 35 mm Oerlikon twin cannon
Type
Place of origin	Switzerland
Service history
Used by	See operators
Specifications
Weight	6,700 kg (14,800 lb) (with ammunition)
Length	7.8 m (25 ft 7 in) (travelling)
Barrel length	3.15 m (10 ft 4 in) (barrel)
Shell	Complete round: 35×228mm, 1.565 kg (3 lb 7 oz)
Caliber	35 mm (1.4 in)
Action	Gas-operated
Carriage	4 wheels with outriggers
Elevation	−5°/+92°
Traverse	Full 360°
Rate of fire	550 rounds/min (per barrel)
Muzzle velocity	1,175 m/s (3,850 ft/s) (HEI-T)
Effective firing range	Ceiling: 4,000 m (13,000 ft)

The Oerlikon GDF or Oerlikon 35 mm twin cannon is a towed anti-aircraft gun made by Oerlikon Contraves (renamed as Rheinmetall Air Defence AG following the merger with Rheinmetall in 2009). The system was originally designated as 2 ZLA/353 ML but this was later changed to GDF-001. It was developed in the late 1950s and is used by around 30 countries.

The system uses twin , firing 35×228mm NATO-standard ammunition. It was originally designated 353 MK and is now designated as the KD series. The same KD series 35mm cannons are used in the Leopard 1 based Gepard and Type 74 tank based Type 87 SPAAG and Marksman self-propelled anti-aircraft guns (SPAAG). The system could be paired with the off-gun (remote) Super Fledermaus fire control radar, which in the late 1970s was upgraded to the Skyguard system. The weapons was aimed either directly, by way of an advanced sighting system, or automatically, by locking onto the target with radar. Early models carried 112 rounds ready to fire, and an additional 126 stored on the chassis as reloads. Later versions with automated reloading carry 280 rounds total. A typical engagement burst is 28 rounds.

In 1980 an upgraded model, the GDF-002 was produced, which featured an improved sight, and the ability to be directed by an off-gun digital control system. A few years later a third version of the system was being produced, the GDF-003, which was broadly similar to the GDF-002, but included some enhancements like self-lubricating weapons and integrated protective covers.

In 1985 a further upgraded model was produced, the GDF-005, which was introduced, featuring the Gunking 3D computer-controlled sight with an integrated laser range-finder and digital control system. The GDF-005 also introduced an automated ammunition-handling system, which eliminated the need for the two reloaders, reducing the crew from 3 to 1.

The guns are usually transported by a 5-tonne 6×6 truck.