Handgun safe design

A note about terminology: Handgun safes must meet four criteria in order to satisfy the needs of gun owners who keep handguns for defensive purposes. First, the device must be small enough to make placement easy. Second, the device must allow for quick access. Third, the controls intervening between the user and the locking mechanism must be minimally complex to operate. Fourth, the device must prevent unauthorized access.

Regardless of what a manufacturer calls a handgun safe—“gun vault,” “lock box,” “pistol box,” “pistol safe” or “portable case”—the above design criteria must apply if the device is to meet the needs of gun owners. Every device examined on this website, accept for gun locks, serves the same function and is therefore a handgun safe. Though California law refers to these devices as “lock boxes,” lock box is a synonym for handgun safe in the discussions on this site.

Characteristics of lock boxes

Lock boxes are designed to allow ready access to firearms kept for defensive purposes, while keeping firearms inaccessible to unauthorized individuals. These devices are not intended to provide fire protection, humidity control, or defense against brute-force attack with large hand tools like pry bars and power tools.

Lock boxes can be divided into two kinds. The less popular devices are made with mechanical pushbutton locks. The more popular and more varied lock boxes on the market are made with electronic locking mechanisms.

Electronic lock boxes typically have five components. The components are 1) a container, including the box, door, hinges, and related hardware, 2) mechanical components of the locking mechanism proper of the safe, 3) electrical components of the locking mechanism proper of the safe, 4) an integrated circuit, or “chip,” and 5) a mechanical bypass lock actuated by a key.

Not every electronic lock box has all five of these components, but the majority of them do. Some electronic lock boxes have no keyed bypass locks. These devices will have an exposed pair of contact points for applying a 9V battery should the batteries fail. Lock boxes having only a mechanical pushbutton lock will have no bypass lock.

Many lock boxes are part of related product lines. A line of related devices will share fundamental characteristics such as an identical locking mechanism, keypad fitting, and paint finish. Often the differences between lock boxes in a related line of products are minor, such as differences in storage capacity. Two devices in a line of related products may be identical in nearly all ways, and differ only in how the user interacts with the circuitry; one device may use a keypad to tell circuitry to power a motor which releases a latch, the other may use a fingerprint reader to tell circuitry to do the same thing.

Locking mechanisms

Lock boxes with electronics can be divided into four groups based on the most commonly used mechanisms installed in them. These are 1) motorized boltwork, 2) motorized latchwork, 3) spring-release latchwork, and 4) solenoid-locked boltwork.

1) Motorized boltwork: As the name implies, a motor is used in these mechanisms to draw the boltwork back and return the bolts to the locked position. This arrangement allows the boltwork to be locked in place by the motor’s gearing when the safe is closed. Though these mechanisms are relatively secure, motorized boltwork mechanisms are slow to actuate the bolts, and don’t offer the quick-release response people want in a handgun safe. Few handgun safes have this kind of mechanism installed in them.

2) Motorized latchwork: Motorized latch mechanisms are diverse. The distinguishing characteristic of these mechanisms is that a motor rotates a fitting designed to nudge or push the latch’s hardware into the open position, releasing the door. The latchwork is not held in place by the motor’s gearing, and is designed to move independently of the motor. Motorized latch mechanisms can be made secure if a manufacturer eliminates extraneous holes in a device that allow access to the mechanical components of the mechanism.

3) Spring-release latchwork: Spring-release latchwork mechanisms are extremely diverse. The distinguishing characteristic of these devices is that two pieces of hardware, a latch and a latch holder (or “release”), are held together in a locked position under spring tension; release of the mechanism involves the latch holder being moved so that the two pieces are no longer held in a stable position, allowing the latch to be thrown open by the spring. As with motorized latchwork mechanisms, the spring-release latchwork mechanism is not held in place by the motor’s gearing. These mechanisms are inherently fast opening, and designers favor them in lock box design.

4) Solenoid-locked boltwork: This is the most common locking mechanism found in small personal safes, though not necessarily in lock boxes. In these mechanisms, a solenoid pin is used as a device to prevent the safe’s boltwork from being retracted until someone enters a correct access code. Depending on the strength of the spring in a solenoid, its magnetic pin may be bounced by shaking or dropping a safe that isn’t bolted down. In an effort to design solenoid-locked safes that are resistant to being bounced or shaken open, designers have arranged internal components in different ways, with solenoids oriented horizontally or upside down.


The most important thing to understand about biometric technology is that a fingerprint reader is not a locking mechanism. The fingerprint reader is simply another part of a safe’s controls and it serves the same function as a keypad. The reason for incorporating biometrics into the controls of a safe is that a fingerprint reader provides the user with a uniquely user-specific form of access code.

However, if a fingerprint reader is going to add any level of security to a safe, the same design considerations pertaining to other handgun safes must be addressed. For example, extraneous holes in a safe that allow access to the mechanical components of a locking mechanism will undermine security regardless of the biometrics. If extraneous holes allow access to the controls for entering and deleting fingerprints, a safe might as well have no fingerprint reader at all.

So, which fingerprint reader is better? Probably none. To understand why that is the case you have to understand something about probability, and I have only the most basic understanding of probability from studying psychology.

If thousands of people are buying thousands of a given handgun safe with a particular fingerprint reader installed, we know that a certain random order, or responsiveness, will emerge from the use of the fingerprint reader. We also know that all those purchasers are, in a sense, running independent trials every time they use their safes. These end up being long trials. The probability that a fingerprint reader will scan a print correctly is a proportion of the times that outcome will occur over a long series of scans. But as far as I know, nobody is collecting this kind of data.

I have personally tested the biometric systems on ten different models of handgun safe, and I’ve learned that these systems are much better than 50% but not quite 100%. Therefore the user of one of these safes will experience long runs of accurate reads followed by streaks of inaccurate reads. Weeks and even months of perfect fingerprint reader scans will pass. Then the biometrics will appear to stumble. More often than not, however, probability is playing tricks with the imagination. The system is likely working just fine.