I have some information, including a 16mm Film that I have never looked at that relates to a 40mm Gatling type weapon intended for use on the A-X ground attack aircraft (later the A-9 and A-10 and then the A-10 with the GAU-8 cannon). I hope to get the film put on a DVD, but the label on the film is
40mm Gun Boosted Rocket
Test Firings of Rounds 119-138
This date was in the middle of the Study process for the A-X weapon. The record of the development of the A-10 indicates that GE, TRW, Philco-Ford were proposing 30mm weapons and Harvey Engineering Lab was proposing a 57mm recoiless weapon. There is no mention of a 40mm Gun Boosted Rocket (GBR). The GE 30mm (GAU-8) was selected and then compared to the Oerlikon 304RK 30 mm (GAU-9).
Either there was another contender, perhaps not serious enough to merit discussion in the A-X study written in 2010, but serious enough in 1969 to write a contract to demonstrate the weapon and conduct test firings. The AF Armament Lab at Eglin was in the middle of this competition and was involved in the testing of the 40mm GBR weapon. The weapon was on display for some time at the Armuor Research Foundation in Chicago before it was cut up and disposed of.
I am hoping some information like the contractor and the development office will be identified on the intro of the film, but this is probably unlikely.
Has anyone heard of this weapon or any other GBR work in the mid-late 1960s or early 1970s???
Any assistance or thougths would be appreciated.