Draw a 32-inch line, lengthwise, across the 2-inch center of your 1-by-4-by-32-inch board. Draw eight perpendicular lines across the first line, spaced 4 inches apart, with the two outside lines 2 inches away from the ends of the board. This board will serve as the top of your gun rack, to hold the barrels.
Drill a 2-inch hole through the board at each intersection of lines. Erase the remaining pencil marks.
Set both boards on edge, so they are parallel and 38 inches apart. Set the plywood on top of the boards so the edges are flush, and drill pilot holes through the plywood and into the boards. The holes should be ½ inch away from the 32-inch edges of the plywood. Space the holes 4 inches apart. Screw the plywood to the boards using eight 2-inch screws.
Sand the rack using the medium-grade and fine-grade sandpaper. Wipe the rack with a tack cloth, and apply the wood stain. Let the stain dry according to instructions on the label.
Locate studs in the wall where you plan to hang your gun rack. Position your rack over the studs with the 1-by-4-inch board on top and parallel with the floor. Use the level to ensure the rack is level, and screw it to the wall using the 4-inch screws. Use one screw for each corner.
Slide the barrels of your guns through the holes, and set the butt-end of your guns on the bottom shelf. The trigger should be facing away from the wall.