Ckm wz.30

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ciężki karabin maszynowy wz.30
Polish partisans firing a ckm wz.30 in 1944
Type	machine gun
Place of origin	Poland
Service history
In service	1930 to ?
Used by	Poland, Romania, Spain
Wars	WW2, Spanish Civil War
Production history
Designed	1930
Produced	1930 to 1939
Number built	+7831
Variants	wz.1930a wz.1930/39T (cal. 7,65 x 53 mm, prototype for Turkish army) wz.33, wz.36 (aircraft guns)
Specifications
Weight	65 kg (gun, tripod, water, and ammunition)
Length	925 mm
Barrel length	720 mm
Cartridge	7,92 x 57 mm Mauser
Caliber	7,92 mm
Action	recoil
Rate of fire	500 round/min
Muzzle velocity	845 m/s
Feed system	250 round belt

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.

[edit] History

After Poland regained her independence in 1918, her armed forces were armed in a variety of completely different weapons, mostly a legacy of the armies of her former occupying powers. Like in the case rifles and carbines, the machine guns used by the Polish Army in the Polish-Bolshevik War varied from Russian 7,62 mm M1910 Maxim to Austrian 1907 8 mm Schwarzlose MG M.07/12 and from German 7,92 mm Maschinengewehr 08 to French 8 mm Hotchkiss Mle 1914. Such a 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 Polish standard 7,92 mm round and fire-proven during the Polish-Bolshevik War, had the most supporters. In late 1924 and early 1925 approximately 1000 pieces of that weapon were ordered in France and the Polish Ministry of War started talks on buying the license for producing the licence-built copies in Poland. However, the first tests of the post-war Hotchkiss machine guns proved that the new production was well below both Polish needs and maker's specifications. Because of that, 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 with Browning M1917, Czechoslovakian-built copy of Schwarzlose M.7/12 (Schwarzlose-Janeček vz.07/12/27) and British Vickers with .303 Vickers. All initial tests were won by the construction of John Browning. The tests were repeated in 1928 and again the American construction proved to be the best. Thus the Polish ministry decided to purchase a license. However, it turned out that neither the Colt company nor its European representative, the Belgian 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 excellent American M1917.

In summer of 1930 the first test models were ready and were sent to various testing ranges. Until March of 1931 first 200 pieces 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 x 57 mm ammunition
2. loophole iron sights replaced with V-notch sights
3. butt handle of the weapon was lengthened for easier carriage
4. Barrel was lengthened 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 AA 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 was received a 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, prepared for export to Turkey and adapted to Turkish standard 7,65 x 53 mm ammunition. However, the design was never introduced in large numbers as the Turkish competition was halted after the World War II broke out. In late 30s, Wilniewczyc and Skrzypinski designed experimental barrels with a rifled oval barrel bore (so called Lancaster Rifling). The barrels were very expensive to produce but features significant increase of the accuracy and longevity of the barrel. Altogether, between 1930 and 1939 7861 pieces of ckm wz.30 were built in the Fabryka Karabinow (Rifle Factory) in Warsaw, most of them for the Polish Army. Small numbers were exported to Republican Spain, Nationalist Spain and Romania.

Polish infantry & cavalry weapons of Polish Defensive War
Side arms and Rifles
rifle wz.98a | rifle wz.29 | pistol Vis
Machine guns & other larger weapons
HMG wz.30 | LMG Browning wz.1928 | AT rifle wz.35 | grenade launcher wz.36
Prototypes & test run weapons
SMG Mors | Semi-automatic rifle wz.38M
Grenades
fragmentation grenade wz.1933 | concussion grenade wz.1933