Four Swiss-made Semag-Oerlikon anti-aircraft cannons, with ammunition for test firing, were the first 20 mm anti-aircraft weapons acquired in Finland in the late 1920s. After the test firing (and the technical problems encountered during the tests), the weapons were made available to the Finnish Civil Guard. As the threat of war loomed large in the late 1930s, more ammunition was acquired. During the Winter War, the Semag-Oerlikons were issued to an anti-aircraft battery protecting the Kiviniemi bridge on the Karelian Isthmus. When the ammunition ran out, the weapons were discarded.

SPECIFICATIONS:

• calibre 20 mm
• muzzle velocity 650 m/s
• effective range 1000 m
• rate of fire 150–170 rounds per minute
• magazine 20 rounds
• firing weight 245 kg

References: Vehviläinen Raimo et al., Itsenäisen Suomen Ilmatorjuntatykit 1917–2000, Sotamuseo, Helsinki 2005; Palmu Pentti, Yön yli päivään – Suomen ilmatorjunnan vaiheita 1925–1990, Ilmatorjuntaupseeriyhdistys Ry, Helsinki 1989; Ilmatorjuntajoukot 1925–1960, Ilmatorjuntaupseeriyhdistys Ry, Helsinki 1963