We claim the ornamental design for a front portion of a stun gun, as shown and described.
FIG. 1 is a perspective view of a front portion of a stun gun, showing our new design;
FIG. 2 is a front elevational view of FIG. 4;
FIG. 3 is a top plan view of FIG. 4, the bottom plan view being a mirror image thereof;
FIG. 4 is a right-side elevational view of FIG. 4; and,
FIG. 5 is a left-side elevational view of FIG. 4.
The broken lines showing a remaining portion of a stun gun depict environmental matter, and form no part of the claimed design. The remaining broken lines shown on the design in the figures represent potential boundry lines for future continuation applications. The rear elevational view constitues no part of the claimed design.