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 various modifications such as greater caliber, longer barrel and adjustable sighting device, it was an improved although unlicensed copy of its predecessor, and was the standard machine gun of the Polish Army since 1929.

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 guns 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 (as the Ckm wz.25 Hotchkiss) 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 Czechoslovakian-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.

Modifications
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:
 * 1) Different calibre, adapted to the Polish standard 7.92×57mm Mauser ammunition
 * 2) Loophole iron sights replaced with V-notch sights
 * 3) Butt handle of the weapon was lengthened for easier carriage
 * 4) Longer barrel for greater precision and accuracy
 * 5) Rifle lock was modified for easier exchange of used-up barrels
 * 6) The lock was modified for easier handling
 * 7) The mounting was adapted for anti-aircraft fire
 * 8) Sights were adapted for anti-aircraft fire as well as a handle for aiming in the air was added

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 by the SEPEWE syndicate to Republican Spain, Nationalist Spain and Romania.

Users

 * 🇨🇦 Canada
 * Nazi Germany
 * 🇵🇱 Second Polish Republic
 * Kingdom of Romania
 * 🇪🇸 Second Spanish Republic
 * 🇪🇸 Nationalist Spain
 * 🇹🇷 Turkey