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).
Relative merits of forward and rear magazines for 40mm guns.
| Identifier | ExFiles\Box 175\3\ img310 | |
| Date | 11th February 1941 | |
| To Rm.{William Robotham - Chief Engineer} from Ve. c.c. Sg.{Arthur F. Sidgreaves - MD} Hs.{Lord Ernest Hives - Chair} C. UDS. Dv. 40 mm. GUNS. Relative Merits of Forward and Rear Magazines. (1) It has been decided to concentrate on the simple spring loaded magazine holding eight to ten rounds, which, by its principle of operation, must always be in the rear position. (2) The B.U.S.M. are to develop a magazine holding, say 16 rounds and capable of being re-loaded from the top. This will be in the forward position. Our reasons for making this decision are :- (a) The rear type Magazine. This is so simple in construction and operation and lends itself so well to use on existing 40 mm. guns, that there is every chance that it can be developed as a reliable job in time to be in service in the near future. (b) The forward type Magazine. Two different schemes produced by this department at an early stage in the development of the 40 mm. gun, showed that it must of necessity be a complicated mechanical problem and as there are delay periods in its time cycle, it will result in a slower gun. We feel that its successful development will take a long time and therefore look on it as our second string. Nevertheless, such a magazine would be more generally acceptable from the installation point of view and every encouragement will be given to its development. The essential technical differences are :- In the rear type of Magazine the round is swept into the feed opening progressively during the runout of the gun assisted by a simple spring loaded deflector arm, which is pushed aside by the breech ring when the gun recoils. The disadvantages of the system are that it ties us to the rear position and that ten rounds is probably the maximum capacity continued. | ||