Missing Numbers in GBU Series
There are a few gaps in the list of confirmed GBU series numbers, which I could not yet track down in official records or popular sources. This article provides a summary about these "missing numbers", and briefly discusses (if possible) which guided bombs might have had the missing numbers assigned. For each missing designation, a rough time frame is given brackets. This denotes the period in which the designation would have been assigned in sequence, based on the time line for the preceding and following numbers.
GBU-4/B [1967-1969]: There is an unconfirmed report saying that the GBU-4/B was a BLU-89/B bomb with a KMU-353/B EOGB (Electro-Optical Guided Bomb) guidance kit. However, the same report attributes the GBU-5/B designation to an EOGB-equipped BLU-90/B, and there are stronger indications that the GBU-5/B slot was actually assigned to a "Rockeye" cluster bomb with Paveway I guidance. Therefore the GBU-4/B EOGB most likely did not exist.
GBU-13/B [1973-1975]: There is one unconfirmed reference ([1]), which says that the GBU-13/B was a CBU-77/B cluster bomb (consisting of a SUU-51B/B dispenser filled with 790 BLU-63/B 0.43 kg (0.95 lb) APAM fragmentation bomblets) with a KMU-422/B Paveway I LGB guidance kit. However, the name "GBU-13" is also sometimes used to describe a British MK 13 bomb with a Paveway kit, and this "GBU-13" might just as well be an official designation (see also GBU-18/B below).
GBU-14/B [1973-1975]: No information whatsoever is available on the GBU-14/B.
GBU-18/B [1976-1980]: The name "GBU-18" is sometimes used to describe a British MK 18 bomb with a Paveway I or Paveway II LGB guidance kit, and this "GBU-18" might just as well be an official designation.
GBU-19/B [1976-1980]: There are spurious references to the GBU-19 as a weapons option (no further details) for the F-117A. However, this notion is not backed up by hard evidence, and most likely false.
GBU-25/B, GBU-26/B [1980-1986]: No information whatsoever is available on these two numbers.
GBU-45/B [2003-2004]: The designation "GBU-45" has been used informally some years ago for BDU-45/B inert concrete bombs fitted with a Paveway II LGB guidance kit. At that time, the GBU-45 designator had not been officially assigned, but it is possible that this has changed by now, or that the official GBU-45/B designation has been skipped to avoid confusion with the existing unofficial use.
GBU-46/B [2003-2004]: No information whatsoever is available on the GBU-46/B.
GBU-47/B: This designation was allocated to a classified USAF weapon in January 2005.
GBU-60/B [?]: No information whatsoever is available on the GBU-60/B.
GBU-63/B, and -65/B through -68/B [2014-2016]: No information whatsoever is available on the these GBU numbers. It's possible that some designations have been reserved for future JDAM-ER variants.
GBU-70/B: The designation was allocated to a guided bomb for the USAF. However, the only public references are National Stock Number listings, and a single Air Force document outlining education and training plans for munitions systems. None of them quotes anything tangible about the GBU-70's characteristics, only the rather generic label "Utility Guided Bomb". The GBU-70/B entries are always very close, and virtually identical in wording, to those for GBU-69/B, so the two are apparently related in some way.
GBU-71/B [2016-2017]: No information whatsoever is available on the GBU-71/B.
References
[1] Hajime Ozu: "Missile 2000 - Reference Guide to World Missile Systems", Shinkigensha, 2000
[2] USAF nomenclature records for GBU series designations
Back to Directory of U.S. Military Rockets and Missiles, Appendix 5
Last Updated: 5 February 2024