The ornamental design for a rifle, as shown and described.
1. Rifle
1.1: Perspective
1.2: Right
1.3: Left
1.4: Front
1.5: Rear
1.6: Top
1.7: Bottom
Fig. 1.1is a perspective view of the design, fig. 1.2is a right view thereof, fig. 1.3is a left view thereof, fig. 1.4is a front view thereof, fig. 1.5is a rear view thereof, fig. 1.6is a top view thereof, fig. 1.7is a bottom view thereof; the parts shown in broken lines are for illustrative purposes only and form no parts of the claimed designs.