20×138mmB
The 20×138mmB cartridge or Long Solothurn is a type of ammunition used mainly for anti-aircraft and anti-tank weapons during World War II. The designation means the caliber is 20 mm, the length of the cartridge case is 138 mm and "B" indicates it is a belted case. The loaded cartridge weighs . History. The 20×138mmB cartridge was initially created by the Swiss Solothurn company in the early 1930s. Users. The 20×138mmB cartridge is used in the following weapons: