File talk:A GAU-12 25 mm Gatling gun static display sits outside the Munitions Materiel Handling Equipment Focal Point building at Eglin Air Force Base, Fla., April 24, 2013 130424-F-OC707-003.jpg

The article about the GAU-12 states that it is a 5-barrel gun, but the weapon in the picture appears to have 6 barrels. Here is the manufacturer's page:

https://www.gd-ots.com/armaments/aircraft-guns-gun-systems/gau12u/

The weapon in the picture looks like the M61 Vulcan:

https://en.wikipedia.org/wiki/File:M61A1-Vulcan--Independence-Day-2017-Tel-Nof-IZE-059.jpg