The barrels were very expensive to produce, but gave a significant increase of the accuracy and longevity of the barrel. Altogether, between 1931 and 1939, the Fabryka Karabinow ("Rifle Factory") in Warsaw built at least 8,401 ckm wz.30 for the Polish Army, in addition to 200 of information series (available are only data until March 1939, and several hundreds more were probably built by September 1939). In addition, quite a big number - over 1,700 - was exported by the SEPEWE syndicate to Republican Spain. There were trials to sell them also to other countries, like Romania, Bulgaria, Estonia, Yugoslavia and Argentina, but in spite of favourable participation in contests, the state factory had no resources to credit deliveries. Among others, in 1936 in Argentina the wz.30 machine gun was evaluated as more reliable and accurate than original Browning M1928, but Colt could ensure more favourable conditions of delivery. In 1938 Turkey ordered 500 wz.30/39T machine guns and probably at least part of this contract was fulfilled. Captured weapons were used by Nationalist Spain, Nazi Germany and Romania. After 1939, many preserved wz.30 machine guns were used by Polish partisan units (mainly Home Army), among others during Warsaw Uprising. Surviving examples Users Second Polish Republic Second Spanish Republic Nationalist Spain :Supplied in small quantities by the Soviet Union in 1940 References world.guns.ru www.1939.pl www.wojsko18-39.internetdsl.pl Erenfeicht, Leszek. Ckm wz.1930, "Wielki Leksykon Uzbrojenia. Wrzesień 1939" No.2. Edipresse Polska, 2013. Further reading 7.92×57mm Mauser machine guns World War II machine guns Heavy machine guns Machine guns of Poland World War II infantry weapons of Poland Science and technology in Poland Military equipment introduced in the 1930s