Deterrent ammunition, including a projectile of soft elastic rupturable material, such as natural or synthetic rubber or plastic, having a charge of flowable material, such as finely divided particulate or powder, carried in a cross-sectionally polygonal cavity having relatively thin longitudinal rupture wall zones along the corners of the cavity and thicker longitudinal strengthening zones bounding the cavity straight wall surface sections, with a generally ogive-forming nose section having an easily flexible annular wall connecting with a thicker and more rigid piston-forming nose end of lesser lateral crosssection than the interior cavity cross-section at the rear end of the flexible annular wall for ease of rearward piston movement of the pistonforming nose end on target impact. The projectile is carried in a cartridge by a bore-riding segmented sabot of low density, low mass material and is ejected from the cartridge by ignition of propellant in the cartridge, which effects gas pressure on an obturating pusher disc engaging with the rear of the segmented sabot.