The Panzerbüchse 39, abbreviated PzB 39, (German: "tank hunting rifle model 39") was a German anti-tank rifle used in World War II. It was an improvement of the ''Panzerbüchse 38 (PzB 38) rifle. Development PzB 38 German anti-tank rifles originated back in 1917 with the Mauser 1918 T-Gewehr, the world's first anti-tank rifle, using a special 13.2 mm (0.52 in) cartridge. It was created in response to the appearance of the first British tanks on the Western Front. That single shot manually operated rifle enjoyed moderate success; approximately 15,800 rifles were built. German development resumed in the late 1930s. In an effort to provide infantry with a man-portable lightweight anti-tank rifle, Dipl.-Ing. (certified engineer) B. Brauer at Gustloff Werke in Suhl designed the Panzerbüchse 38 (PzB 38). It was a manually loaded single-shot weapon with a recoiling barrel, using a special 7.92 mm (0.311 in) cartridge. When fired, the barrel recoiled about , which opened the breech and ejected the spent cartridge casing. The breech block was then arrested in the rear position, remaining opened for the gunner to manually insert a new cartridge. The gunner then released the cocked breech with a lever at the grip. The breech and barrel would then move forward again and the trigger was cocked in preparation to fire. This rather complicated mechanism was reportedly prone to jamming as the system got dirty in field use. Although manufactured with pressed steel parts that were spot-welded, because of the complicated vertical breech block mechanism it was difficult to manufacture and only a small number of 1,408 PzB 38 rifles were built in 1939 and 1940 at the Gustloff Werke plant; 62 of these weapons were used by German troops in the invasion of Poland in 1939. The rifle was long - folded for transport - and weighed . It used a specifically designed cartridge with a standard caliber of 7.9 mm, but a very large 94 mm long case (nominal 7.92×94mm). also known as the "7.92 x 94 Patronen". PzB 39 The next development, onto which production was immediately switched, was the Panzerbüchse 39 (PzB 39), an improvement made by Gustloff on their PzB 38. It also used a vertical breech block mechanism and the same cartridge as the PzB 38. It retained the barrel of the PzB 38 and had an only slightly increased overall length of ; weight was reduced to . Performance