The 155 mm M-83 howitzer was originally developed and produced by Tampella, which then became known as VAMMAS Ordnance and more recently Patria Weapon Systems.

The Finnish Army designation for this system is the 155 K 83. United Nations sources state that Finland did not export any 155 mm artillery systems between 1992 and 1998. Between 1999 and 2000 Finland exported only one 155 mm artillery system. This was a 155 mm/52 calibre system to Egypt based on the Patria Weapon Systems 155 mm 155 GH 52 APU. This is called the EH52 as it is not fitted with an APU. Licence production of this is now being undertaken in Egypt for the Egyptian Army. This is carried out by the Abu Zaabal Engineering Industries Company.

Patria Weapon Systems has completed production of their 155 mm 155 GH 52 APU and is now concentrating on its 120 mm mortar systems.

The 155 mm M-83 howitzer has a split trail carriage and can be fitted with a 39 or 45 calibre ordnance which has a distinctive T-type muzzle brake. As an alternative to the normal 155 mm ordnance, the gun can be supplied with a 122, 130 or 152 mm barrel allowing Chinese/Russian types of ammunition to be fired rather than 155 mm NATO-type ammunition.

The semi-automatic horizontal sliding breech mechanism and a special loading mechanism enable a high rate of fire to be achieved with obturation being obtained by a steel ring.

The special loading system is operated by compressed air, with the cylinder for the latter located on the right side of the mount. The sights, elevation and traverse wheels are located on the left side of the mount.

According to Patria Weapon Systems, the weapon is very easy to handle with only a few men required to bring the weapon into firing or travelling configuration. When in the travelling configuration the ordnance is traversed through 180° and locked in position over the closed trail legs. When in the firing position the weapon is supported on a firing jack under the forward part of the carriage and on the two trails, each of which is fitted with a spade. Steel stakes are provided for the spades and these are carried in racks on the inside of each trail.

The 155 mm M-83 fires the standard NATO M107 HE projectile as well as hollow base and two types of base bleed projectile, one type with nubs and the other without.

The design of the charge system is optimised so that range areas cover each other in low- and high-elevation angles. Compared to the standard NATO charge system (at least four different charges), the Patria Weapon Systems system consists of three different charges, incremental charge and two types of full charges.

The make-up of the incremental charge is similar to NATO charges M4A2 and M3A1, including four increments, zones 5, 6, 7 and 8. Full and top charges are similar to NATO M2 and M11, zones 9 and 10. The latter is only used in the 155 mm 45 calibre gun.

Some 155 mm M-83 systems have been observed fitted with a muzzle velocity radar measuring system over the ordnance. This feeds information to the fire-control computer.

Details of the latest Patria Weapon Systems version with a 155 mm 52 calibre ordnance and an APU are given in a separate entry. This system is designated the Patria Weapon Systems 155 mm GH 52 APU and in late 1997 was ordered by the Finnish Defence Force with first deliveries taking place early in 1998.

A total of 54 weapons have been built for Finland. Production is now complete and it is no longer marketed.