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).
Blueprint showing the arrangement and clamping of four rounds or cylinders.
| Identifier | ExFiles\Box 176\1\ img086 | |
| Date | 20th September 1940 guessed | |
| .950 CRS 90° 21.S.W.G. (.032) 2ND ROUND ¢ 1ST ROUND ¢ 30° R | ||