We claim the ornamental design for a rifle shoulder harness, as shown and described.
FIG. 1 is a front view of the rifle shoulder harness.
FIG. 2 is a rear view of the claimed design.
FIG. 3 is a left side view of the claimed design.
FIG. 4 is a right side view of the claimed design.
FIG. 5 is a top view of the claimed design.
FIG. 6 is a bottom view of the claimed design; and,
FIG. 7 is a perspective view of the claimed design.
The broken lines representing a person in FIG. 7 are for illustrative purposes only and form no part of the claimed design. The remaining broken lines represent top stitching.