From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Magazine capacity and performance of a 40mm ground defence gun.
| Identifier | ExFiles\Box 144\4\ scan0200 | |
| Date | 28th December 1940 | |
| Ye. from Rm.{William Robotham - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} and Hs.{Lord Ernest Hives - Chair} c. EV.{Ivan Evernden - coachwork} He file Rm.{William Robotham - Chief Engineer}16/ML.28.12.40. 40 mm. GROUND DEFENCE GUN. Since the successful test of the 40 mm. gun on the 15 cwt. truck, the General Staff have apparently been giving it some consideration. Brigadier General Neville Smith [illegible]d told me they had decided that an 8-round magazine was insufficient unless the charge could be replenished in a very brief space of time, say one or two seconds. An aircraft in a dive-bombing attack covers half a mile in 6 seconds. He stated that they would be content with a magazine that could not easily be replenished, if it could fire a continuous burst of 16 rounds. We pointed out that the merit of the Rolls Royce 40 mm. gun lay in its simplicity and the few man-hours which it took to produce and that if they were going to ask it to do all that the Bofors does they would finish up with the same type of weapon and no useful result would have been achieved. The fact remains however, that if the B.U.S.M. magazine functions satisfactorily, it can be made to hold 16 rounds. We do not think that the Army comments should affect our existing programme at the moment, as otherwise we shall never get the fully automatic gun firing even 8 rounds. If and when we have a successful 8-round magazine, and the B.U.S.M. magazine, it may be possible to effect a compromise between mechanical complication and a continuous burst of 16 rounds. Rm.{William Robotham - Chief Engineer} | ||