(certified engineer) B. Brauer at Gustloff Werke in Suhl designed the Panzerbüchse 38 (PzB 38).

When fired, the barrel recoiled about 9 cm (3.5 in), 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.

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.

It retained the barrel of the PzB 38 and had an only slightly increased overall length of 162.0 cm (5 ft 3.8 in); weight was reduced to 12.6 kg (28 lb).

These converted rifles received the designation Granatbüchse Modell 39 (GrB 39) and remained in use until the end of the war.