We stumbled upon this U.S. Navy photograph in the National Archives and just thought it was too cool not to share. 

The official caption describes it as a machine gun on a bore-sighting stand as part of the Navy's Aviation Free Gunnery Unit at Barber’s Point, Hawaii, taken on Aug. 18, 1943. 
 

The machine gun on the stand seems to be an ANM2, a .30-06 chambered version of the M1919 Browning machine gun meant for aircraft use, with a wicked rate of fire that could touch 1,500 rpms.

Twin .30-cal ANM2s were mounted in the rear seats of Dauntless and Helldiver dive bombers, Avenger torpedo bombers, and in the blisters of the PBY-5 Catalina. 

They were also pressed into service by Marines on the ground. One notable image from the attack on Pearl Harbor shows Marines on Ford Island using an ANM2, likely borrowed from a Navy PBY, set up to take shots at incoming Japanese planes. 

Other images show Marines on Okinawa with a full twin mount, likely plucked right from a wrecked Helldiver or SBD, and used for defense in a ground attack role. 
 

It was little wonder that some Marines took these super-rapid machine guns and fitted them with stocks, triggers, and bipods to make so-called "Stinger" LMGs. See Medal of Honor recipient Marine Corporal Tony Stein for more information on that. 

Ian McCollum over at Forgotten Weapons covered that tale back in 2019.