Pressed and segmented gas generant grain assemblies formed from a plurality of symmetric gas generant pieces or segments are disclosed. The symmetric pieces or segments are arranged circumferentially to define a substantially round, segmented body. In certain variations, the symmetric segments are substantially free of polymeric binder and have a high density. The segmented pressed grain assemblies are more robust and less expensive to manufacture, while still exhibiting desired combustion performance. Methods of making such segmented gas generant grain assemblies are also provided.