A rotary drill bit for engaging an earth strata material includes a cutting insert attached to an axial forward end of an elongate drill bit body. The cutting insert includes an elongate insert body rotatable about a central axis with a pair of symmetrical halves symmetrical about the central axis, each symmetrical half comprising: a leading face; a top surface having a primary relief surface; a web thinning gash extending between the leading face and the primary relief surface, the web thinning gash having a debris evacuation portion centrally disposed adjacent the central axis and a distal transition portion disposed adjacent the debris evacuation portion; a first leading cutting edge at the intersection of the leading face and the primary relief surface; and a second leading cutting edge at the intersection of the web thinning gash and the primary relief surface of the top surface.