Firearm support and rest assemblies having nested stacking geometries are disclosed herein. One embodiment of the disclosure, for example, is directed to a firearm rest assembly for supporting a firearm having a first section spaced apart from a second section. The firearm rest assembly includes a base having a lower surface spaced apart from an upper surface, and an intermediate surface positioned between and generally parallel to the lower and upper surfaces. The firearm rest assembly further includes first and second supports coupled to the base in a configuration selected from a stored arrangement and a support arrangement. The stored arrangement includes the first and second supports positioned between the lower surface and the intermediate surface, and the support arrangement includes the first support extending from the base beyond the upper surface to support the first section of the firearm, and the second support extending from the base beyond the upper surface to support the second section of the firearm.