11mm Pin fire
When WW1 ended the Germans had to disarm its armed forces, and that lead to some interesting stories.
One is that Sweden bought German tanks to arm Sweden, our first tanks here.
In the same time, Sweden bought tools to manufacture the German Mauser antitank gun m/1918. If we bought it directly from Germany or from some other source is unknown to me yet. This resulted in a trial model of the gun named antitank rifle fm/21. It was a direct copy of the German gun.
The ammunition is the same as the German, 13x92R that is a necked and rimmed rifle cartridge. The cartridge was manufactured in Sweden and stamped with the same tool as for a 6,5x55 case. The projectile is an armor piercing construction with a plane steel jacket and steel core.
Source: A splendid text named "The cartridges of the Mauser anti-tank rifle of 1918 and of the T.u.F M.G. made by M.A.N, written by Manfred Stegmuller.
Thanks to Morten Støen for providing me with this text.