The DP-27 is a light machine gun designed for the Soviet Red Army in the 1920s under the leadership of Vasily Degtyaryov (1880-1949), the first test model being the DP-26. Two test guns were manufactured and fired 5,000 rounds each from September 27–29, 1926, during which weaknesses were discovered in the extractor and firing pin mechanisms. After design improvements, two more guns were made and tested in December 1926, firing 40,000 rounds under adverse conditions, resulting in only .6% stoppages. However, changes to the bolt carrier and the chamber locking mechanism were still required. After this redesign the improved gun, now called the DP-27, was tested by the Red Army at the Kovrov plant on January 17–21 of 1927, passing all tests and being approved for manufacture. A full year of service testing followed, after which the primary requested change was the addition of the large flash suppressor that is now considered one of the recognition features of the design. With further refinements, the DP was to be the primary light machine gun of the Red Army during WWII.