The period of service of the Bristol Scout (1914–1916) marked the genesis of the fighter aircraft as a distinct type and many of the earliest attempts to arm British tractor configuration aircraft with forward firing guns were tested in action using Bristol Scouts. These began with the arming of the second Scout B, RFC number 648, with two rifles, one each side, aimed outwards and forwards to clear the propeller arc.
Two of the Royal Flying Corps' early Bristol Scout C aircraft, numbers 1609 and 1611, flown by Captain Lanoe Hawker with No. 6 Squadron RFC, were in turn armed with a Lewis machine gun on the left side of the fuselage, almost identical to the manner of the rifles tried on the second Scout B. using a mount that Hawker had designed. When Hawker downed two German aircraft and forced off a third on 25 July 1915 over Passchendaele and Zillebeke he was awarded the first Victoria Cross for the actions of a British military pilot in aerial combat.
Some of the 24 initial production Scout Cs for the RNAS, were armed with one (or occasionally two) Lewis machine guns, sometimes with the Lewis gun mounted on top of the upper wing centre section in the manner of the Nieuport 11; more common was a very dubious choice of placement by some RNAS pilots, in mounting the Lewis gun on the forward fuselage of their Scout Cs, just as if it were a synchronized weapon, firing directly forward and through the propeller arc; an action likely to result in serious damage to the propeller. The type of bullet-deflecting wedges that Roland Garros had tried on his Morane-Saulnier Type N monoplane were also tried on one of the RFC's last Scout Cs, No. 5303 but since this seemed to have also required the use of the Morane Type N's immense "casserole" spinner, which almost totally blocked cooling air from reaching the engine, the deflecting-wedge method was not pursued further with Bristol Scouts.
A RNAS Scout was the first landplane to be flown from a ship, when Flt. Lt. H. F. Towler flew No. 1255 from the flying deck of the seaplane carrier HMS Vindex on 3 November 1915. As an attempted defence against German airships some RNAS Scout Ds were equipped with Ranken Darts, a flechette with 1 lb (0.45 kg) of explosive per projectile, released from a pair of vertical cylindrical containers under the pilot's seat, each containing 24 darts. On 2 August 1916, Flt. Lt. C. T. Freeman flew a Scout from the deck of Vindex and attacked Zeppelin L 17 with Ranken Darts. None of the darts did any damage to the Zeppelin, and since Freeman's aircraft could not land on the Vindex and was too far from land for a safe return, he had to ditch his Scout D after the attack.
In March 1916, RFC Scout C No.5313 was fitted with a Vickers machine gun, synchronised to fire through the propeller by the awkward Vickers-Challenger synchronising gear, the only gear available to the RFC. Six other Scouts, late Scout Cs and early Scout Ds, were also fitted with the same combination. Types using this gear (including the B.E.12, the R.E.8 and the Vickers F.B.19) all had the gun mounted on the port side of the fuselage. The attempt to use the gear for synchronising a centrally mounted gun on the Bristol Scout failed and tests, which continued at least until May 1916, resulted in the abandonment of the idea and no Vickers-armed Bristol Scouts were used on operations.
None of the RFC or RNAS squadrons operating the Bristol Scout was exclusively equipped with this aircraft and by the end of the summer of 1916, no new Bristol Scout aircraft were being supplied to the British squadrons of either service, the early fighter squadrons in RFC service being equipped instead with the Airco DH.2 single seat Pusher configuration fighter. A small number of Bristol Scouts were sent to the Middle East (in Egypt, Mesopotamia and Palestine) in 1916.Others served in Macedonia and with the RNAS in the Eastern Mediterranean. The last known Bristol Scout in military service was the former RNAS Scout D No. 8978 in Australia, which was based at Point Cook, near Melbourne, as late as October 1926.
Once the Bristol Scouts were no longer required for front line service they were reallocated to training units, although many were retained by senior officers as personal "runabouts".