The cone-bore principle was first patented in 1903 by a German designer, Karl Puff.
In the 1920s and 1930s, another German engineer, Gerlich, conducted experiments with coned-bore barrels that resulted in an experimental 7 mm anti-tank rifle with a muzzle velocity of 1,800 m/s.

Based on these works, Mauser-Werke AG developed a 28/20 mm anti-tank weapon initially designated Gerät 231 or MK.8202 in 1939–1940.
In June–July 1940, an experimental batch of 94 (other sources say 30) pieces was given to the army for trials.
They resulted in some modifications and in 1941 mass production of what became 2.8 cm schwere Panzerbüchse 41 started.
One piece cost 4,520 Reichsmarks (for the sake of comparison, one 5 cm Pak 38 gun cost 10,600 Reichsmarks).
The last gun was built in 1943; the main reason for the discontinuance was the lack of tungsten for projectiles.
The cone-bore principle was first patented in 1903 by a German designer, Karl Puff. In the 1920s and 1930s, another German engineer, Gerlich, conducted experiments with coned-bore barrels that resulted in an experimental 7 mm anti-tank rifle with a muzzle velocity of 1,800 m/s.
Based on these works, Mauser-Werke AG developed a 28/20 mm anti-tank weapon initially designated Gerät 231 or MK.8202 in 1939–1940. In June–July 1940, an experimental batch of 94 (other sources say 30) pieces was given to the army for trials. They resulted in some modifications and in 1941 mass production of what became 2.8 cm schwere Panzerbüchse 41 started. One piece cost 4,520 Reichsmarks (for the sake of comparison, one 5 cm Pak 38 gun cost 10,600 Reichsmarks). The last gun was built in 1943; the main reason for the discontinuance was the lack of tungsten for projectiles.
2.8 cm sPzB 41