In 1951, the Technical Section of the Swiss General Staff carried out a study to see if an MBT could be designed in Switzerland. This study concluded that it was possible and two years later design work on the first Swiss MBT began at the now Swiss Ordnance Enterprise (previously k + w Thun). On 1 January 1999 the company was renamed SW Swiss Ordnance Enterprise Corp.

The first prototype of the Swiss MBT, designated the KW30, was completed in 1958 and armed with a Swiss-designed 90 mm gun. The second prototype was completed the following year. These two prototypes were followed by 10 preproduction tanks, Pz 58 (Panzer 58), built between 1960 and 1961 and armed with a British 20 pounder (83.4 mm) gun as installed in the Pz55. In March 1961, a production order for 150 Pz 61s (armed with a British 105 mm gun) was placed, with deliveries to the Swiss Army taking place between January 1965 and December 1966.

The Pz 61 MBTs were all phased out of service with the Swiss Army by late 1996.

Further development of the Pz 61 resulted in the Pz 68. The first prototype of this was completed in 1968 with production being authorised the same year.

Between January 1971 and July 1974, a total of 170 Pz 68 Mk 1s were delivered to the Swiss Army. Main differences between the Pz 61 and Pz 68 can be summarised as the installation of a stabilisation system for the 105 mm gun to allow the Pz 68 to engage targets accurately while moving across country, ammunition supply hatch in the left side of the turret, more powerful MTU engine coupled to a modified transmission, wider tracks with replaceable tracks and greater length of track in contact with the ground.

The Pz 68 has been upgraded on a number of occasions including the installation of the thermal sleeve for the 105 mm gun and the installation of the Bofors Lyran system (Swiss Army designation 7.1 cm Le GW 74) on the turret roof between the commander's and loader's positions. This can launch an illuminating rocket to a maximum range of 1,300 m.

A total of 390 Pz 68 series MBTs were built for the Swiss Army. As of early 1999 a total of 186 Pz 68 were in service together with 186 of the upgraded Pz 68/88 covered in detail later in this entry.

In January 1998 it was stated that the unmodified Pz 68 MBTs would be phased out of service by the year 2000.

The hull of the Pz 68, like its turret, is a one-piece casting supplied to Thun by Georg Fischer of Schaffhausen, and is divided into three compartments: driver's at the front, fighting in the centre and the engine at the rear.

The driver is seated at the front of the hull in the centre and is provided with a one-piece hatch cover hinged at the rear. Three day periscopes are mounted forward of the hatch.

The turret h^s no bustle, is in the centre of the hull with the commander and gunner seated on the right and the loader on the left. The commander's cupola has eight periscopes and a single-piece hatch cover that opens to the rear. The commander also operates the split image coincidence rangefinder which has a magnification of x8. The gunner is seated forward and below the commander and has a periscope with a magnification of x8 and x2.7. The loader's cupola is provided with six vision blocks and split hatch covers that open left and right. The loader's cupola is a little higher than the commander's whose area of observation is therefore restricted.

The engine compartment is at the rear, separated from the fighting compartment by a fireproof bulkhead. The complete power pack, consisting of the engine, auxiliary engine, transmission, cooling and exhaust system, can be removed from the vehicle in about one hour. The MTU engine was supplied by Germany and is coupled to a Swiss SLM transmission consisting of a semi-automatic gearbox with six forward and two reverse gears and a double-differential steering system with a hydrostatic steering drive providing progressive and continuous steering control.

The suspension of the Pz 68 consists of six dual rubber-tyred roadwheels, each independently located and sprung by Belleville washers. The idler is at the front and the drive sprocket at the rear. There are three track-return rollers. The tracks of the Pz 68 are of cast manganese and have no rubber pads.

Main armament of the Pz 68 is a British-designed Royal Ordnance 105 mm L7 series gun manufactured in Switzerland with a number of modifications, known as the Pz Kan .61 and firing a Swiss-designed HE round (muzzle velocity 600 m/s) in addition to the normal APDS (muzzle velocity 1,470 m/s), HESH (muzzle velocity 730 m/s) and smoke rounds. Switzerland has adopted the Israel Military Industries M111 APFSDS projectile. The gun control system for the Pz 68 is a French SAMM Type CH 25 electrohydraulic system similar to that developed for the French AMX-30 MBT.

Mounted on the forward part of the loader's hatch is a 7.5 mm MG 51 machine gun for anti-aircraft defence which can be elevated from -4 to +77°, and mounted on either side of the turret are three L Pz 51 (80.5 mm) smoke grenade dischargers.

Standard equipment on the Pz 68 includes an NBC system, a hull escape hatch and a drinking water tank. There is no provision for deep fording.

• Pz 68 Mk 2

This was approved for production in 1974 at a cost of SFr146.3 million, and is basically the Pz 68 Mk 1 with an alternator, a thermal sleeve for the 105 mm main armament, and a system for extracting carbon monoxide. Between March and December 1977, 50 Pz 68 Mk 2 tanks were delivered to the Swiss Army.

• Pz 68 Mk 3

This has all the improvements of the Mks 1 and 2 but also has a larger turret. Production was authorised in 1975 at a cost of SFr447 million and 110 tanks were delivered between 1978 and September 1979.

• Pz 68 Mk 4

This is similar to the Mk 3 and 60 were ordered in 1978 for delivery between July 1983 and April 1984. The Pz 68 Mk 4 cost SFr207 million. In general the terms Mks 1, 2, 3 and 4 are not used in Switzerland. They are normally called the 1st, 2nd, 3rd (or Pz 68/75) and 4th series.

• Pz 68 Upgrade

It was announced in early 1988 that 195 Pz 68 MBTs were to be upgraded by the installation of a new fire-control system supplied by Honeywell's German subsidiary and licence-built in Switzerland by Contraves. The fire suppression system would also be upgraded with all work being carried out at Swiss Ordnance Enterprise Thun where the Leopard 2 (Pz 87) was built. Of the total of 195 Pz 68 MBTs to be upgraded, 25 will be from the second batch (Pz 68 Mk 2) with the remainder all of the third (Pz 68 Mk 3) and fourth (Pz 68 Mk 4) batches. When upgraded the Pz 68 was redesignated the Pz 68/88.

Additional modifications will include a muzzle reference system and a primary stabilised sighting system for the gunner with an eyepiece for the tank commander. Suspension was upgraded with hydraulic bump stops and an improved collective NBC system will be fitted. New paint will be introduced and the steel fuel tanks will be replaced by GRP tanks.

• 120 mm gun for Pz 68

Swiss Ordnance Enterprise has developed a 120 mm smoothbore gun called the Compact Tank Gun to the prototype stage. This has been successfully trialled in a Pz 68 MBT of the Swiss Army.

The available 120 mm guns would not fit into the relatively small Pz 68 turret and no extensive turret modifications were allowed; also a moderate trunnion load was required. For interoperability reasons the gun was required to fire the same ammunition as the Leopard 2 MBTs used by the Swiss Army.

The barrel calibre length was increased to L/49 compared to the L/44 of the Leopard 2, the front end of the barrel has a dovetail attachment enabling a muzzle reference sensor to be installed. The barrel is also fitted with a fume extractor of filament-wound glass fibre composite.

The breech is the semi-automatic vertically sliding wedge type with an electrical firing system.

• Anti-aircraft Tank

The prototype of this system, which had the same twin 35 mm turret as fitted to the German Gepard SPAAG, was handed over to the Swiss Ordnance Procurement Agency in April 1979. It has been decided that the system will not be procured.

• ARV

• Armoured Bridgelayer

• 155 mm Self-propelled Gun

The prototype of a 155 mm self-propelled gun called the Panzer-Kanone 68, based on the chassis of a Pz 68 MBT, was built some time ago. It was not placed in production as the Swiss Army procured additional US 155 mm M109SPGs.

• Target Tank

A special version of the Pz 68, called the Panzerzielfahrzeug or PzZielfz68, has been developed for training anti-tank crews. It has a heavily armoured turret with a dummy gun and additional armour is provided forthe hull. The tops ofthe tracks are covered by armoured skirting. The Pz Zielfz 68 weighs 38,000 kg and has a crew of two.

Production complete. In service only with the Swiss Army.