The ornamental design for a firearmrail mount, as shown and described.
FIG. 1 is a perspective view of the firearm rail mount embodying the new design;
FIG. 2 is a left side view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a front view thereof;
FIG. 7 is a rear view thereof; and,
FIG. 8 is a bottom perspective view of the firearm rail mount being inserted in a mount body.
FIGS. 1-8 show features of a firearm rail mount in broken lines. These features do not form any part of the claimed design. The broken lines immediately adjacent the solid line portions of the design form the boundary of the design, with the broken lines forming no part of the claimed design. The firearm rail mount is shown with a symbolic break in its length. The appearance of any portion of the firearm rail mount between the break lines forms no part of the claimed design.