Ckm wz . 30 Ckm wz . 30 ( short for " ciężki karabin maszynowy wz . 30 " ; " heavy machine gun Mark 1930 " ) is a Polish - made clone of the American Browning M1917 heavy machine gun . Produced with only minor modifications , it was an unlicensed copy of its predecessor and was the standard machine gun of the Polish Army . Design and development . After Poland regained her independence in 1918 , her armed forces were armed with a variety of different weapons , mostly a legacy of the armies of her former occupying powers . As with their rifles and carbines , the machine gun s used by the Polish Army in the Polish - Soviet War included Russian 7 . 62 mm M1910 Maxim , Austrian 1907 8 mm Schwarzlose MG M . 07 / 12 , German 7 . 9 mm Maschinengewehr 08 and French 8 mm Hotchkiss Mle 1914 . Such diversity was a logistical nightmare , and in the early 1920s the General Staff of the Polish Army decided to replace all older machine guns with a new design , specifically built to Polish designations . Initially the Hotchkiss machine gun , adapted to the standard Polish 7 . 92 mm round and proven during the Polish - Soviet War , had the most supporters . In late 1924 and early 1925 approximately 1 , 000 were ordered from France and the Polish Ministry of War started talks on buying the license for manufacturing copies in Poland . However , the first tests of the post - war Hotchkiss machine guns proved that the new production were well below both Polish needs and maker ' s specifications , and the talks came to a halt . By the end of 1927 the ministry organized a contest for a new standard all - purpose heavy machine gun . Only three companies took part in the competition : the American Browning company with the Browning M1917 , a Czechoslovakia n - built copy of Schwarzlose M . 7 / 12 ( Schwarzlose - Janeček vz . 07 / 12 / 27 ) and the British Vickers machine gun . All initial tests were won by Browning . The tests were repeated in 1928 , and again the American weapon proved to be the best so the Polish ministry decided to purchase a license . However , it turned out that neither the Colt company nor its European representative , the Belgian company Fabrique Nationale de Herstal , had patented the design in Poland . In addition , the documentation of a recently purchased license for Browning Automatic Rifle of the same designer was faulty . Because of that , the Polish ministry decided to order the preparation of a local version of the Browning M1917 . In mid - 1930 the first test models were ready and were sent to various testing ranges . In March 1931 the first 200 models were sent to front - line units for further tests under the designation of Ckm wz . 30 . Among the most notable differences between the original and the Polish clone were : Following the first tests , a series of additional modifications was introduced . In 1938 the trigger mechanism was replaced with a completely new , more reliable system . In addition , the lock was replaced for easier handling and keeping the weapon in good condition . The modified design received the designation of " ckm wz . 30a " , though the name was rarely used by the soldiers themselves . The new version was also the basis of a " ckm wz . 30 / 39T " design , designed for export to Turkey and adapted to Turkish standard 7 . 65×53mm Argentine ammunition . However , the design was never introduced in large numbers as the Turkish competition was halted after World War II broke out . In the late 30s , Wilniewczyc and Skrzypinski designed experimental barrels with a rifled oval barrel bore ( " Lancaster rifling " ) . The barrels were very expensive to produce , but gave a significant increase of the accuracy and longevity of the barrel . Altogether , between 1930 and 1939 , the " Fabryka Karabinow " ( " Rifle Factory " ) in Warsaw built 7 , 861 ckm wz . 30 , most of them for the Polish Army . Small numbers were exported to Republican Spain , Nationalist Spain and Romania .