2. The improved self-destruct mechanism of claim 1 wherein: said nose cap is a tubular member having a closed forward end with a circumferential pattern of holes in the rearward extension thereof; said spring-actuated striker means comprises: a striker member having a pointed end in juxtaposition with said detonator, a cylindrical plunger member lying within said nose cap and having a flangular extension on the end thereof distal proximate said closed forward end of said nose cap, said plunger further in line with said striker member, and a helical spring surrounding said plunger member positioned between said flangular extension and said closed forward end; and said detent means comprises a plurality of ball members disposed within said holes in said rearward extension of said nose cap acting against said flangular extension of said plunger holding said helical spring compressed, said detent means further including a circumferential groove in the inner wall of said opening in said ogive in a location forward of the position of said ball members disposed within said holes when said nose cap is fully engaged in said opening, whereby said ball members are forced outwardly into said groove upon movement of said nose cap forward, thereby releasing said plunger member, forcing said striker member into said detonator causing self-destruct.

3. A fuse for a spinning projectile subject to decreasing velocity after launch due to drag forces acting on said projectile comprising delayed arming impact means having a firing pin and a detonator for delayed arming and for firing of a munition subject of setback, spin, and impact, in combination with velocity-responsive apparatus of claim 3 having movable means for receiving a drag force dependent on relative velocity with respect to a fluid medium, spring means for acting on said movable means in opposition to said drag force and actuator means operatively connected to said firing pin, for providing a mechanical output in response to movement of said movable means by said spring means in opposition to said drag force, whereby said mechanical output fires said detonator after the velocity of said projectile drops to a predetermined level.