I claim the ornamental design for a firearm grip, substantially as shown and described.
FIG. 1 is a top perspective view of a firearm grip in accordance with the present design, the broken lines depicting certain internal structures being shown for illustrative purposes only and form no part of the claimed design;
FIG. 2 is a right side view of the firearm grip shown in FIG. 1, the broken lines depicting a fastener being shown for illustrative purposes only and form no part of the claimed design;
FIG. 3 is a left side view of the firearm grip shown in FIG. 1;
FIG. 4 is a bottom view of the firearm grip shown in FIG. 1;
FIG. 5 is a top view of the firearm grip shown in FIG. 1, the broken lines depicting certain internal structures being shown for illustrative purposes only and form no part of the claimed design;
FIG. 6 is front view of the firearm grip shown in FIG. 1; and,
FIG. 7 is an exemplary diagram of the use of the firearm grip, the broken lines being shown for illustrative purposes only and form no part of the claimed design.