Ready Use Pyrotechnic Store (Building 77) immediately to the north-west of Hangar 3 at former RAF West Raynham

The Ready-Use Pyrotechnic Store (Building 77) is located immediately to the north-west of Hangar 3 at the former RAF West Raynham. It was constructed in 1937/8 based on designs by JH Binge from the Air Ministry's Directorate of Works and Buildings, following an original design by Archibald Bulloch.

The building is made of monolithic concrete and has a rectangular shape, aligned from north-east to south-west. On the main north-west side, there are three fire-proof steel doors made by Dorman Long and Co Ltd of Middlesbrough. The rear elevation features three original ventilation grilles set in the plinth, along with three later 20th-century ventilation grilles below the eaves in modified openings that once held plate glass windows. The side walls are blind.

Inside, the building is divided into three storage cubicles. The westernmost cubicle still has its original set of nine brick-built cupboards with steel doors. While the other two cubicles were not inspected, they are likely to have similar cupboards.