This is a replacement tip for Nerf type foam darts. The warhead is intended to be printed in a flexible material, and features a hollow point, so that a small "pop-it" noisemaker charge can be inserted, effectively creating an explosive tipped dart. The darts, however, will perform just fine without the charge.

The design is patterned after the streamlined Nerf dart, and has been verified to operate correctly in magazine fed blasters.
http://youtu.be/vbKdHL00LGQ