The armament industry was an important part of the interwar Czechoslovak economy and made up a large part of the country's exports (see, for example, Bren light machine gun, which was a modified version of the Czechoslovak ZB vz. 26). However following the 1948 communist coup d'état, all heavy industry was nationalized and was (at least officially) cut off from its Western export market behind the Iron Curtain. While most other Warsaw Pact countries became dependent on armaments imports from the Soviet Union, most of the Czechoslovak weaponry remained domestic (for example, the Czechoslovak army used the Vz. 58 assault rifle, while other communist bloc countries used variants of the AK-47).