http://www.af.mil/news/factsheets/AC...U_Gunship.html:
Primary Function: Close air support, air interdiction and force protection
Armament: AC-130H/U: 40mm cannon and 105mm cannon
http://www.theaviationzone.com/facts/ac130.htm:
Beginning in 1973, Project Pave Spectre II upgraded all but one of the AC-130Es with new Allison T56-A-15 turboprops, the latest radio, avionics and ECM gear, a 105mm Howitzer cannon and inflight refueling capability. These aircraft were redesignated AC-130H.
Другими словами, правда стоит 105mm пушка, howitzer или по Русски гаубица.