FIG. 1 is a perspective view of a air grease gun showing my new design thereof; FIG. 2 is a front elevational view thereof; FIG. 3 is a rear elevational view thereof; FIG. 4 is a left elevational view thereof, FIG. 5 is a right elevational view thereof, FIG. 6 is a top plane view thereof; and, FIG. 7 is a bottom plane view thereof.