The ornamental design for a shotgun sling mount, as shown and described.
FIG. 1 is an isometric projection of a front side view of a shotgun sling mount showing my new design;
FIG. 2 is an isometric projection of a rear side view thereof;
FIG. 3 is an top plan view thereof;
FIG. 4 is an elevational view of a front side thereof;
FIG. 5 is an bottom plan view thereof;
FIG. 6 is an elevational view of a first side thereof;
FIG. 7 is an elevation view of a second side thereof; and,
FIG. 8 is an elevational view of a rear side thereof.
The broken lines in the figures are for illustrative purposes only and form no part of the claimed design.
The broken lines showing of environmental structure in FIGS. 1, 2, 4, and 8 are for the purpose of illustrating environment only and forms no part of the claimed design.