The ornamental design for a pistol-grip drinking glass, as shown and described.
FIG. 1 is a perspective view of the pistol-grip drinking glass;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an additional perspective view thereof.
Shade lines of varying lengths are used in the figures. Each shade line is a solid line terminating with a white space followed by a dot or a short dash. The shade lines are only for the illustrative purpose of showing shading and form no part of the claimed design.