[3] After World War II the primary fixed light coastal guns in Finland were older heavy anti-aircraft guns on fortification mounts that were obsolete in air defence duties and had been transferred to coastal artillery, primarily 76 ItK 16 V and 76 ItK 31 ss.

In 1966 yliluutnantti Juhani Niska submitted a proposal to use modified 100 mm T-54 tank turret as coastal gun.

The proposal compared also Swedish 75 mm Bofors turret gun and 76 ItK 31 ss as other possibilities.

The sustained fire rate is 6 rounds per minute and the muzzle velocity is 880 metres per second (2,900 ft/s) with HE-FRAG shells.

A fully automatic loading system would have taken too much space, and simple counterweight operated shell hoisting mechanism was developed to transfer ammunition up to the turret.

New periscopes were ordered from Yugoslavia, but the break-up of the nation and the resulting Yugoslav wars caused delays.

Externally the most visible change was new thermal insulation dome on top the turrets that also gives them a more rock-like appearance for camouflage.

However, in the end a domestic development work began in the beginning of the 1990s on shells suitable for naval engagements.