The second prototype of the F-35A (first flight 21 April 2010 and delivered to Edwards 17 May 2010) was used in a series of tests with the internal 25 mm GAU-22/A 4-barrel rotary cannon. The gun is seen here, uncovered and mounted internally near the left wing root. The gun carries 182 rounds and is effective against ground targets. AF-02 is seen here in a test area of Edwards. The Lightning II and its gun were directed to a distance huge sand wall in which the 25 mm rounds were fired.