The ornamental design for a firearmrail mount, as shown and described.
FIG. 1 is an upper perspective view of the firearm rail mount embodying the new design;
FIG. 2 is a lower perspective view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a front view thereof; and,
FIG. 8 is a rear view thereof.
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.