Can anybody enlighten me as to the whys and wherefores of the red paper [?] covers on the leading edges of RAF Spitfires?
I believe it was to keep the gun muzzles clean during takeoff. Once in the air, the first burst would tear it open and not impede fire.
Dragonfly
It was tape, actually. It kept debris out of the gun bays, but it also indicated a malfunctioning gun is the tape wasn’t blown out after firing.
Regards, Rick
So it would come on a roll like sellotape but wider and was replaced before each take-off?
I don’t know if it came in a roll but if I am not mistaken I beleive it was kind of like modern day duct tape. Yes it was to keep the gun bays clean and was replaced every time the guns were armed.
actually the practice was similar to those used by the US Navy and the USAAF during the same period.
The tape over the gun ports was an adhesive backed fabric tape, easily torn into squares to place over the gun ports. I’ve got a video copy of a TV special on the history and development of the Spitfire, and it uses lots of footage from RAF training films, and it has a short segment on the ways they used to protect the guns from debris.
if you paint the non sticky side of tan colored masking tape red and cut it into little squares it would have the same effect on a model Spitfire or Hurricane.
LOL that must be how they coined the term Red Tape
Thank you people - that has cleared it up for me - Here in the UK they’re showing ‘A Spitfire’s Story’ on Discovery Wings @ 7pm & 10pm so I’ll be taping that for reference later… 
For the Battle of Britian GB I did a Hurricane Mk. I. I used small squares of red tissue/wrapping paper. Look on about page 78 or 79 for a photo…