Comments by "Neil of Longbeck" (@neiloflongbeck5705) on "The BIG bang behind Britain's iconic Spitfire \u0026 Hurricane, with firearms expert, Jonathan Ferguson" video.

In 1934 the Air Ministry started looking at better guns for future fighter aircraft. This was around the same time as they were also looking at what would become the Spitfire and Hurricane. They tested 0.303in and 0.50in machine guns and the 20mm Hispano cannon (which was new and unreliable at the time). The 0.303in machine gun gave the best rate of fire and was selected.
3
@88porpoise in 1940 they did and they got jams after a few fired rounds and the pilots of 19 Squadron asking for their old aircraft back. Better an ineffective weapon than a useless weapon.
1
@88porpoise IIRC there were no other 0.50in machine guns (neither Vickers or Browning) in regular use with the British military at that time and so there was no appetite for another supply chain. They stopped almost all aircraft development in 1940 to concentrate on defence using what was already in service or planned to come into service. It took until after the Battle of Britain was long over before a reliable wing-mounted cannon was developed.
1