ROF Featherstone was one of around 20 World War II munitions filling factories. As of 2020 most of the site has now been destroyed/developed, including for use as two prisons and a DVSA driving centre.

Filling factories such Featherstone had a large number of buildings which were divided into Groups based on their purpose in the filling of munitions. Explosives magazine buildings in each Group stored the incoming explosive materials and outgoing filled shells or gun cartridges. Storage buildings were also needed for each Group to store the incoming empty shells and the empty ammunition boxes.

For safety purposes, munitions were segregated into different compatibility Groups. A World War II Filling Factory would generally fill several different Groups of Munitions; and these Groups would be located in different geographical areas within the Danger Area of the Filling Factory.

The World War II Groups were:

  • Group 1: Initiators, such as caps and detonators for primers and fuzes.
  • Group 2: Fuze pellets, exploder pellets, exploder bags.
  • Group 3: Filling of fuzes.
  • Group 4: Blending of gunpowders for time fuzes.
  • Group 5: Filling of cartridges, such as filling cordite into cloth bags or into brass cartridge cases.
  • Group 6: Manufacture of smoke producing compositions.
  • Group 7: Small arms filling.
  • Group 8: Filling of shells or bombs.
  • Group 9: Large magazines, filled ammunition awaiting dispatch.

In addition, a Filling Factory would have provision for limited proofing and testing of its munitions; and burning grounds for disposal of waste explosive material.

Outside of the Danger Area, but still within the factory site, would be located other buildings such as:

  • administration offices;
  • pay offices;
  • workshops;
  • a medical centre;
  • changing rooms;
  • contraband storage (for items prohibited in the Danger Areas, e.g. matches, tobacco, etc.);
  • search rooms;
  • canteens (as many as 40 in some of the large factories).