From 1936-1940, BLM supplied many parts for field armourers using the 'duv' identification code. On a small scale, the company made M1928 flare guns and MG34 bolt parts and barrels. BLM invented the hammer forged barrel process, which speeded up production substantially. On August 25, 1944, 81 B-24s of the American Eighth Air Force conducted a bombing raid over Lübeck, heavily damaging the BLM factory and killing or wounding 58 of the facility's workers and air raid personnel.