Trigger locks (Figure 12) can be purchased in a variety of styles, all of which secure the handgun by immobilizing the trigger. The most common trigger lock design covers the trigger mechanism on either side with two steel or plast ic blocks that lock together. The locks can be purchased with in either keyed or combination styles, and are designed to allow the handgun to be transported while locked. Most trigger lock designs are easy to use; however, the owner of the handgun must actively install a trigger lock.

Some handgun owners may wish to use a trigger lock to secure a loaded gun. In such cases, the risk of unintentional discharge is significant when installing or removing a trigger guard. If the trigger lock does not fit the gun properly or is improperly installed, the trigger may still be operated. When properly installed on unloaded handguns, trigger locks can reduce the risk of unintended discharge. Trigger locks prevent children of any age from using the gun, as long as the child d oes not have access to the key or combination.

A wide variety of handgun safety devices are manufactured that insert into the barrel or chamber of the gun and provide a physical barrier against loading the handgun.

A barrel insert can be a metal rod, a plastic plug, or a plastic cable that inserts through the barrel and blocks the chamber (Figure 13). Another style of barrel insert is a plastic pin that inserts into the barrel attached to a strong rubber band which hooks around the back of the hammer, securing it in place.

Chamber inserts differ from barrel inserts in that they are placed directly into the chamber rather than inserted through the barrel. They are designed to hold the action in an open position.

All of these designs are relatively easy to use and come in both locking and non-locking styles. Barrel and chamber inserts prevent unintended discharge as long as they are properly installed, because they physically prohibit a cartrid ge from being placed in the chamber. These devices rely on the owner to actively use the insert. Like trigger locks, locking barrel or chamber inserts limit the unauthorized use of the handgun by children and adolescents.

Lockboxes (Figure 14) are small, portable, safe-like boxes or cases specifically designed for the storage and/or transport of handguns. They allow easy access to the handgun and can be purchased with either keyed or combination loc ks. Many are designed to be permanently mounted in a variety of locations. Because they are portable, lockboxes are not as secure as an immobile safe. Lockboxes require the user to actively secure the handgun in the lockbox.

When a handgun is properly secured in a lockbox, it is virtually impossible to unintentionally discharge the weapon. A lockbox effectively prevents the unauthorized use of the gun by children of any age, as long as the child does not ha ve access to the key or combination. The lockbox is the device most often recommended by police to prevent unauthorized access to a handgun.