Abstract: A random time delay fuze includes a fuze base member containing a cylindrl cup guide carrying a slidably mounted cylindrical cup. The cup contains a piston which has a recess slidably mounted on a cylindrical firing pin guide which is also attached to said fuze base and contains a spring biased firing pin. The cup has a ribbon stabilizer, which when exposed to an airstream pulls the cup forward a limited distance, thereby forming a space within the cup between the piston and the cup. The piston is provided with a "floating" O-ring seal, which allows air to flow into but not out of said space, and an air restrictor, which restricts the flow of air out of said space. A biasing spring forces the piston forward in said space, causing air to be vented through the restrictor and thereby retarding the forward movement of the piston. When the piston has moved forward sufficiently, it permits locking balls to release the firing pin.