The Martin Baker MB3 had 6 x 20mm cannon and there were projected fits for the Typhoon of 6 x 20mm cannon, 4 x 20mm cannon and 4 x 0.303”MG and 2 x 20mm and 8 x 0.303” MG. Does anyone know what the magazine capacity in these combinations were compared to the 4 x 20mm that was eventually decided on? Could the Tempest/Fury series have been armed with 6 x 20mm cannon?
The MB3 was supposed to have 200 rpg (although I don't know where they would all fit!). The Typhoon had 140 rpg, around 120 rpg was typical for 20mm cannon RAF fighters. Experience showed that they rarely fired more than 100 rpg in combat. Tony Williams: Military gun and ammunition website and Discussion forum
200 ( some sources say up to 220 ) rounds per gun, and it could carry more fuel than the Typhoon as well, in spite of being smaller. However, one question that to my knowledge remains unanswered is if the M.B.3s wing had the structural integrity needed to fire the six 20mm cannons simultaneously.
