The ornamental design of a muzzlebrake for a firearm, as shown a and described.
FIG. 1 is a front perspective view of a muzzle brake for a firearm according to the new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front end view thereof;
FIG. 4 is a rear end view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is a partial cross sectional view taken from FIG. 6 showing the profile of one of the holes and a depression in the surface associated with the hole.
All broken lines shown in the drawings represent interior portions of the muzzle brake for the purpose of illustrating environmental structure that forms no part of the claimed design.