The ornamental design for a shotgun, as shown and described.
FIG. 1 is a rear, top and right side perspective view for shotgun, showing my new design;
FIG. 2 is a right side elevational enlarged view thereof;
FIG. 3 is a left side elevational enlarged view thereof;
FIG. 4 is a rear elevational enlarged view thereof;
FIG. 5 is a front elevational enlarged view thereof;
FIG. 6 is top plan enlarged view thereof;
FIG. 7 is bottom plan enlarged view thereof; and,
FIG. 8 is a front, top and left side perspective view thereof.
The evenly spaced broken lines are for purposes of illustrating portions of the shotgun that form no part of the claim. The dash dot dash lines are for annotating the cut-offs for the enlarged views.