I cut through the drywall, lag bolted a 2x4 to the studs, drilled two holes through the back of the safe, and lag bolted the safe to the horizontal 2x4. The faces of the 2x4 and the baseboard are almost flush. It is also in a closet, and fits with about 1/2" on either side, so really no access except the door and the top.
Liberty is 'Freedom To' not 'Freedom From'
When they kick in your front door,
How you gonna come?
With your hands on your head,
Or on the trigger of your gun?