Security forces recovered two improvised semi-automatic rifles from the scene of Wednesday night’s shooting atrocity in Tel Aviv.Named after the original Swedish 1945 submachine gun, this type of weapon has come to be known as the “Carl Gustav” or the “Carlo,” and they have proliferated across the West Bank in recent years. Due to its simple construction, copies made of the Carl Gustav design are crudely manufactured (without serial number) by unofficial gunsmiths. The gun weighs 3.3 kg unloaded, and takes a 36-round box magazine.Security forces have, over the past several months, stepped up attempts to gather intelligence and launch raids on the metal workshops, often located in private homes, that produce these guns.The Shin Bet (Israel Security Agency), IDF and police are all working to uncover as many weapons manufacturing workshops as possible, since the Carl Gustav rifle has become the weapon of choice for Palestinian terrorists.According to security sources, the weapons are cheap to manufacture, and require no special technology.“Many have the capability of producing them,” one security official said on Thursday.The weapons are unreliable and frequently jam, as one did during Wednesday night’s deadly attack. Yet they pose a deadly threat, and are proliferating. Security forces regularly report seizing the firearms during weapons raids in Palestinian villages, town and cities.Such efforts will go on, and likely intensify, in the days and weeks ahead.