You can secure one or more firearms using cable locks or trigger locks. Trigger locks can prevent use, but not prevent theft.
If securing several firearms, consider a safe or a locking cabinet. These can be bolted to a floor or wall for extra theft prevention.
Handguns can be kept in small office safe, long guns can be kept in a tall safe, or if needed, a critical part of the long gun such as the bolt or firing pin can be kept in an office safe. This is not as secure as storing the whole firearm in a safe, but can prevent unauthorized use.
These are inexpensive or can be obtained for free some police departments and firearms dealers and local firearms organizations. A firearms lock is included with any recent firearm purchase, often this is a are cable lock.
Example of a cable lock:
The lock, securing a semi-automatic pistol through the magazine well:
Securing the semi-automatic pistol through the barrel:
Securing a revolver, through the barrel:
Securing a revolver, through the chambers in the cylinder:
Even old revolvers can be secured with a cable lock:
Securing a pump-action shotgun through the ejection port:
In a bolt-action rifle, by removing the bolt, and threading the cable lock through the area the bolt occupies:
Small Bio-metric Safes
This type of safe is used to store one or two firearms at-the-ready in a bedroom or under the counter at a store or office, and reads the fingerprint of authorized users. It can open in about one second with a short swipe of your finger across the reader.