I think most of the metal gun safes on the market today come with predrilled holes, and/or "knockouts" that allow for anchoring systems. Some come with simple hardware, others don't.

One of the simplest and most secure....above "grade" safes that I saw installed was done by simply running four short lengths of steel cable through the bottom of the safe and attached to fasteners (but not until after installation). In turn these cables were attached to small square steel plates on the other end. The "steel anchor plates" were emplaced when the concrete was poured. After the concrete cured the safe was move on top....the cables ran inside through the "bolt holes" and fastened and tightened using the fasteners. Incredibly cheap....and strong. Short of someone busting out the concrete floor....that safe wasn't moving!

And for those that are indeed truly serious about safes....there is at least one company I know that installs their safes "below grade" when the concrete is being poured. It is accessed through a flush mounted hardened steel locking system. The contents are stored underground on a "lazy susan" style configuration that turns to allow access to all the contents. It is not cheap....nor easily installed as an afterthought. But it is very secure. Overkill for most home owners!

And finally, for someone on a very tight budget, that doesn't give a hoot about looks....but wants something to secure valuables in either a basement, garage, or out of sight storage compartment....don't overlook "roadside construction boxes". They are very tough, cost effective, can be portable....or anchored....and will secure your valuables as well as the best finished safes going for much more money!

A little of something for everyone!