Here is a little on the flare pistol i found on wikipidia,,Webley & Scott flare pistols
No.1 Mk 1 Flare Pistol on display at the National Firearms Museum
1918 MkIII flare pistol
Webley & Scott produced a number of single-shot, break open signal flare gun devices used by Commonwealth Military Forces during the First and Second World Wars. Perhaps the most prolific of these was the No.1 MkIII, produced in 1918 at the company's Birmingham facility. A variant, differing only in its use of black plastic grip panels instead of the earlier wood, was produced by Colonial Sugar Refinery in Sydney, Australia in 1942. The pistols can often be seen in films, notably Lawrence of Arabia, where the title character discharges one to signal the beginning of an attack on a disabled enemy train, and The Empire Strikes Back where bounty hunter Boba Fett is seen carrying one as a rifle.