The ornamental design for a rifle, as shown and described.
FIG. 1 is a perspective view of a rifle, showing our new design;
FIG. 2 is a right side view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a front view thereof; and,
FIG. 7 is a rear view thereof.
The broken line showing of a portion of the rifle in FIGS. 1 through 6 is included for the purpose of illustrating environment and forms no part of the claimed design.