Open the gun safe and inspect the bottom of the safe for mounting holes. If there are mounting holes in the bottom of your gun safe, skip ahead to step six.
Measure 2 inches from each inside corner of the gun safe with the tape measure and place a mark on the gun safe's floor with the permanent marker to establish where you will drill the gun safe's mounting holes.
Align the tip of the center punch with a mounting hole location mark and hit the back of the center punch with the hammer to make a depression in the surface of the gun safe floor. Repeat the process to make four indentations on the floor of the gun safe. Wear your safety glasses while you are doing this.
Drill a 3/16-inch pilot hole with the variable speed drill at each depression you made on the floor of the gun safe and then exchange the 3/16-inch drill bit for the 1/2-inch drill bit and enlarge each 3/16-inch pilot hole to 1/2 inch.
Wipe the gun safe floor with a clean rag to remove metal shavings from the area.
Slide the gun safe into position and slide the permanent marker into each mounting hole to place four marks on the surface of your floor. Slide the gun safe away from the intended location to allow you ample room to access the marks on the floor.
Insert the 5/16-inch drill bit in the variable speed drill if you are bolting the gun safe to a wood floor, or place the 3/8-inch masonry drill bit into the hammer drill if you are drilling into concrete.
Mark 4 inches on the drill bit with the tape measure and the permanent marker to create a depth gauge.
Drill a hole at each location marked on the surface of the floor. Clean the drilled hole as recommended by the manufacturer. This holds especially true for the concrete expansion bolts.
Place a lag bolt (for a wooden floor) or concrete expansion bolt (for a concrete floor) into each mounting hole in the base of the gun safe. Follow the installation instructions for the concrete expansion bolt.
Attach the 9/16-inch socket to the 3/8-inch ratchet handle and tighten each fastener to finish bolting the gun safe to the floor of your home.