Made Special for the RAF 303 Cartridges

[browningautorifle]

I believe that they could fire the .303 MG's continuously only for about 18 seconds.

Yes, they didn't carry that much ammo either, not like the movies make you think.

"The short answer is about 15 seconds of total fire, delivered in seven to eight two-second bursts.
A Spitfire MKI and II had eight (8) Browning .303 machine guns, each with 300 rounds and a rate of fire, when sustained, at 1,150 rounds per minute. A total weight of 2,400 rounds was carried. Each gun delivered about 19 rounds per second, so 152 rounds per second total.
The Air Ministry found in tests, (the ones that determined eight guns vs. the previous two and then four per wing), that a two second burst at close range, meaning closing in below 300 yards, with eight guns, gave the best effectiveness and balanced armament weight with maneuverability. A two-second burst would deliver over 300 rounds potentially in a 6-foot circle at 300 yards."

Here's another thing about these rounds, specific to aircraft and not to be used by ground troops.

" Early Spitfires at the time of the Battle of Britain had 8 .303 Browning machine guns normally they had 4 guns loaded with SA Ball MKVII Same round was used in the Lee Enfield. 2 guns were loaded with W1 or W1Z armor piercing and 2 with B MKVI incendiary rounds . This was a new development first made by a Belgian inventor called De Wilde and then modified at Woolwich arsenal for mass production a true incendiary bullet that only burned if it hit something. Incendiary tracer was also used. Neither the B MKVI or W1 were used in Lee Enfield Rifles, Ball MK7 was probably only used on aircraft until production of W1 and B MKVI could replace it.

Interestingly the B MKVI was adopted by the USAAF and USN in .30 and .50 a simplified version was developed and used by both UK and US forces, it was particularly devastating against Japanese aircraft."