Firearms safety has been at the forefront of responsible gun ownership for well over a century. As early as 1860, the trigger guard emerged as one of the first universally adopted safety features. Gun safeties have evolved significantly over the years, ranging from active safeties like levers to passive mechanisms such as firing pin blocks.
Today’s firearms incorporate a wide range of safety mechanisms. Some require deliberate action by the shooter, while others operate automatically in the background. Understanding how these systems work — and what they do and do not do — is essential for anyone who owns, carries or trains with a firearm. Let’s delve into the intricate world of gun safeties, breaking down their types and focusing on specific aspects that cater to both beginners and seasoned shooters.
What Is a Firearm Safety?
A firearm safety is a mechanical feature designed to reduce the risk of an unintended discharge. Safeties do this by blocking the trigger, hammer, striker or firing pin until specific conditions are met. Some safeties are manually engaged by the shooter, while others are passive and function automatically.
It’s important to understand that safeties are supplemental devices. They do not replace safe gun handling, proper training or responsible decision-making.
Early Revolver Safety Systems
After the introduction of the trigger guard, early revolvers used a half-cock notch in the gun lock. Most revolvers were single-action, and the half cock notch caught the hammer if you slipped during the cocking process, preventing the hammer from firing.
Some designs went further, such as the Colt 1860, which featured a safety cylinder that allowed the hammer to rest between cylinders — one of the first of its kind. And the Starr revolver was factory-equipped with such a device.
However, most revolvers were carried with an empty cylinder under the hammer to increase safety.
Passive Revolver Safeties
By the 1880s, revolver safety technology improved dramatically with the development of the rebound-type hammer. The hammer spring ran the hammer forward to fire the revolver; then the rebound spring moved the hammer away from the cartridge and kept it there.
Hammer blocks were universal in quality double-action revolvers by 1900 but lagged behind for many years in single-actions. Though not altogether nonexistent, manual trigger and hammer-locking safeties were rare on revolvers.
The passive safety transfer bar, positioned between the hammer and firing pin, marked a milestone in revolver safety. A passive safety requires no active manipulation. As the trigger is fully pressed, the transfer bar rises. The hammer falls and transfers energy to the transfer bar, and the transfer bar strikes the firing pin. That releases the trigger, and the hammer springs back. This innovation has made modern concealed carry revolvers some of the safest ever manufactured
Revolver design is also responsible for a common feature on single-action self-loading pistols: the grip safety. The grip safety would lock the action until the revolver was firmly grasped and the lever depressed. These were called hammerless revolvers, as the hammer was concealed and could not be cocked for single-action fire.
Safety Devices in Semi-Automatic Pistols
With the introduction of self-loading pistols came a dizzying number of safety devices. Practically all that are in use today were invented before 1920.
Inertia Firing Pins
The most important early development was the inertia firing pin. Firing pins were once full-length and rested on the primer of a chambered cartridge. Inertia firing pins are shorter than the firing pin channel and do not rest on the primer when the hammer is down. The hammer smacks the firing pin on firing and drives it forward, firing the pistol. The firing pin is then retracted to its original position by the firing pin spring.
Firing Pin Blocks
The firing pin had its drawbacks, though. If the gun is dropped on the muzzle, the firing pin may take a run forward and fire the pistol. There are two means of making the pistol drop-safe and preventing a negligent discharge. Widely used in single-action automatic pistols is the use of an extra-power firing pin spring and lightweight firing pin to reduce firing pin inertia.
The other type is the firing pin block or drop safety. The firing pin or striker is held in place until the trigger is fully pressed, firing the pistol and moving the firing pin block out of the way. Firing pin blocks are now basically universal.
Introducing Grip Safety
The Colt 1911 handgun introduced a unique combination of safety features. A grip safety, often found in single-action self-loading pistols, locks the action until the firearm is firmly grasped and the lever is depressed. These prevented a cavalryman from shooting his own horse if the pistol were dropped. And the slide-lock safety allowed carrying the pistol hammer to the rear with safety on, making for a very rapid first shot with increased accuracy.
Manual safeties allow the shooter to physically lock the action or firing mechanism. Slide-mounted and frame-mounted safeties differ ergonomically but serve the same purpose: preventing the gun from firing until disengaged.
The slide-lock safety and grip safety were eventually complemented by firing pin blocks or extra-power firing pin springs. The original SIG P210 used this type of trigger-blocking safety. While effective, they are difficult to use quickly.
One safety feature designed to catch the hammer from falling is the half-cock notch. However, this is not a safe carry position. The half cock notch is not strong enough and would drop the hammer if bumped hard enough. Never carry a single-action pistol on half cock!
Magazine Disconnect Safeties
Later single-action safety levers sometimes lock the hammer but not the slide and allow the pistol to be loaded while on safe. An uncommon safety feature today is the magazine disconnect. A magazine disconnect prevents a pistol from firing when the magazine is removed, even if a round remains chambered. The Browning High Power and Smith & Wesson 39/59/5906 pistols, among others, use this “magazine safety.”
Double-Action Safety Systems
The iconic handguns of the past have left a lasting legacy on firearm design and safety features. The Walther P38, a trailblazer of the 1930s, introduced the concept of the double-action first-shot design, setting the stage for subsequent handguns like the Beretta 92 combat pistol.
The innovative safety lever of the Walther safely dropped the hammer from full cock. The hammer fell but was blocked from striking the firing pin by the safety itself. Double-action pistols sometimes use two-piece firing pins as well. With the safety applied, the trigger is inoperable, and the hammer cannot rest on the firing pin. This is a very solid system widely adopted.
The SIG decocker is an ergonomic design located in front of the trigger guard. Originally developed in 1938 for the JP Sauer, this lever was necessary as the pistol had a concealed hammer that could not be lowered manually. In the original design, a hard press on the decocker would cock the hammer for single-action fire. This pistol also featured a manual safety on the slide. Slide-mounted safety levers are not as ergonomic as those mounted on the frame but are positive in function. The SIG decocker was adopted for the highly successful SIG P220 and later P series pistols. Though it has safety features, there is no manual safety.
The CZ 75, in its original design, introduces a selective double-action concept, where the safety cannot be applied when the hammer is down. This unique approach ensures the first shot is fired double-action, with subsequent shots allowing for the application of the safety. While not designed explicitly for carrying cocked and safety on, the CZ 75 offers a practical solution for tactical movement without compromising safety.
Striker-Fired Safety Systems
In contemporary times, striker-fired polymer-framed handguns have become immensely popular, with models like the Glock leading the way. These firearms, predominantly double-action-only, prioritize simplicity and reliability. Glock, for instance, incorporates a firing pin block and a trigger lever within the trigger face, preventing lateral discharge if the trigger is snagged. Some models may include a manual safety, offering an additional layer of control for users who prefer it.
True Safety
It’s crucial to understand that while mechanical safeties are valuable, true safety ultimately lies with the shooter. Regardless of the firearm’s design and safety features, responsible gun ownership, proper firearms training and adherence to safety protocols are paramount.
From the early days of trigger guards and half-cock notches to the sophisticated safety features of modern handguns, each development has contributed to the overarching goal of ensuring firearm safety. The legacy of iconic handguns and the innovations of contemporary designs remind us that safety is not just a feature. It’s a philosophy that embraces a mindset of continuous learning, responsible gun ownership and a commitment to safety.
This article is a compilation of previous blog posts authored by Bob Campbell and Beth Alcazar.
Gun Safeties FAQ
What is a firearm safety?
A firearm safety is a mechanical feature designed to reduce the risk of an unintended discharge by blocking the trigger, hammer, striker or firing pin until specific conditions are met.
What are the main types of gun safeties?
Common firearm safety mechanisms include manual safeties, grip safeties, trigger safeties, firing pin blocks, transfer bars, drop safeties and magazine disconnects. Some are manually engaged, while others function automatically.
Are guns without manual safeties safe?
Many modern firearms rely on internal safety systems rather than external manual safeties. These designs can be very safe when combined with proper handling and training.
What is the difference between a manual safety and an internal safety?
A manual safety requires deliberate action by the shooter to engage or disengage it. An internal safety operates automatically in the background and does not require user input.
What is a drop safety?
A drop safety prevents the firearm from discharging if it is dropped. This is often accomplished through firing pin blocks, transfer bars or internal striker safeties.
Do striker-fired pistols have safeties?
Yes. Striker-fired pistols typically use multiple internal safeties, such as trigger safeties and firing pin blocks, even if they lack a traditional external safety lever.
Is a grip safety the same as a manual safety?
No. A grip safety disengages automatically when the pistol is held properly, while a manual safety must be intentionally switched on or off by the shooter.
Gun Safety Mechanisms Comparison Table
| Safety Type | How It Works | User Action Required | Common Platforms |
| Manual Safety (Thumb/Slide) | Physically blocks firing mechanism | Yes | Semi-auto pistols |
| Grip Safety | Prevents firing unless grip is depressed | No (automatic) | 1911-style pistols |
| Trigger Safety | Blocks trigger movement until pressed correctly | No (automatic) | Striker-fired pistols |
| Firing Pin Block | Blocks firing pin until trigger is pulled | No (automatic) | Most modern pistols |
| Transfer Bar | Prevents hammer from striking firing pin unless trigger is pulled | No (automatic) | Modern revolvers |
| Magazine Disconnect | Prevents firing when magazine is removed | No (automatic) | Select semi-auto pistols |
| Decocker | Safely lowers hammer without firing | Yes | DA/SA pistols |
