I claim the ornamental design for an oval shaped firearm bag, as shown and described.
FIG. 1 is an isometric view of an oval shaped firearm bag showing my new design.
FIG. 2 is a front elevation view thereof.
FIG. 3 is a rear elevation view thereof.
FIG. 4 is a left side elevation view thereof.
FIG. 5 is a right side elevation view thereof.
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines are for environmental purposes only and form no part of the claimed design. The design shown is not to be limited to any particular size and may be scaled larger or smaller.