The ornamental design for a handguard for a firearm, as shown and described.
FIG. 1 is a left side elevation view of a hand guard for a firearm attached to a firearm showing our new design;
FIG. 2 is a left, front, bottom view of the hand guard for a firearm of FIG. 1;
FIG. 3 is a left, front, top view of the hand guard for a firearm of FIG. 1;
FIG. 4 is a right side elevation view of the hand guard for a firearm of FIG. 1;
FIG. 5 is a bottom plan view of the hand guard for a firearm of FIG. 1;
FIG. 6 is a left side elevation view of the hand guard for a firearm of FIG. 1;
FIG. 7 is a top plan view of the hand guard for a firearm of FIG. 1;
FIG. 8 is a front elevation view of the hand guard for a firearm of FIG. 1; and,
FIG. 9 is a rear elevation view of the hand guard for a firearm of FIG. 1.
The broken lines showing portions of the design in all figures are included for the purpose of illustrating environment and unclaimed features and form no part of the claimed design.