Manual safety devices are typically a switch, button, or lever which disconnect the trigger, hammer, or firing pin which require active manipulation to engage and disengage. The purpose of an external manual safety is to reduce the possibility of a negligent discharge: An unintentional discharge of a firearm generated by operator negligence.
Not all firearms feature external safety devices, and there’s a good reason why: Some firearm designs do not need an external manual external safety.
These firearms use passive internal and other types of safety devices to prevent accidental discharges (unintentional discharges caused by mechanical failure, faulty ammunition, or excessive heat buildup), and they are safe to carry, handle, and store as long as the 4 Rules of Gun Safety are observed.
Examples of passive internal safeties include drop safeties, firing pin blocks, and transfer bars which prevent a firearm from discharging unless the trigger is pulled. A double-action trigger would be considered a passive external safety since it requires a focused, intentional effort to properly actuate.
Firearms that lack passive internal safeties would require an external manual safety to block or disconnect the trigger for safe carry and handling.
In the age of modern firearms, there is authoritative consensus that firearms should employ some form of mechanical safety, whether internal or external. Some firearms employ both, but many firearm designs would experience impaired function if an extraneous manual safety is tacked on.
The only surefire safety “device” is maintaining proper trigger discipline. A gun won’t go off if it is carried, handled, and stored in accordance with the 4 Rules of Gun Safety. Any mechanical safety device, including external manual safeties, can fail. In the end, reliance that creates complacency is fundamentally unsafe.
For beginners, this guide will provide a comprehensive overview of the different types of mechanical safety devices to educate and inform a new and prospective firearm owners of their options when selecting a firearm.
Overview of Internal Safety Devices
Internal safety devices are passive safety devices which are integral to the mechanical function of a firearm. They are designed to prevent discharge of a loaded and chambered firearm unless the trigger is pulled, and they function by blocking the firing pin, blocking the firing pin, or they are necessary to connect the hammer to the firing pin.
Drop safeties are designed to prevent unintended discharge when a firearm is dropped, impacted, or jostled. They block or disengage a portion of the firing pin unless the trigger is pulled.
Firing Pin Block
A firing pin block prevents the firing pin from making contact with a chambered cartridge. This block moves out of the way only when the trigger is pulled.
A hammer block prevents the hammer from making contact with a firing pin or a cartridge. It operates in a similar fashion to a firing pin block by moving out of the way only when the trigger is pulled.
Firearms which use a transfer bar utilize a gap between the firing pin and hammer; the transfer bar connects the hammer and firing pin only when the trigger is pulled. This device is commonly used on revolvers to prevent unintentional discharge caused by drops and impacts.
Overview of External Safety Devices
External safeties are usually active safety devices which engage, disengage, or block the trigger mechanism. While most people are familiar with the concept of a manual lever safety, there is a spectrum of external safety devices designed to reduce chances of unintentional firearm discharge.
More commonly found on older firearms, a safety notch involves a notch cut into the base of the hammer. This notch prevents a hammer from falling onto a loaded chamber if the hammer is only partially retracted and is accidentally released. It also prevents the hammer from falling onto a loaded chamber caused by drops or impacts. While technically an internal safety device, the safety notch must be activated externally with deliberate engagement of the hammer.
A manual safety can take the form of a lever, button, or switch, often accessible by the thumb or trigger finger on the firing hand. A manual safety functions by blocking the trigger mechanism, preventing the trigger from being pulled as long as the safety is working and engaged. Some manual safeties also block the hammer or firing pin.
A grip safety is a lever or button built into the grip where it contacts the hand. A grip safety blocks or disengages the trigger until it has been toggled off by the natural grip of a firearm. It is usually positioned in the rear portion of the grip to make contact with the webbing of the hand. There are a few examples where the grip safety is located in the front portion of the grip requiring an affirmative squeeze with the firing hand.
Firearms with a magazine disconnect require a magazine to be inserted into a firearm to disengage the internal safety. When a magazine is not inserted, the gun cannot be fired with its trigger mechanism blocked or disengaged. Magazine disconnects have been deemed unsafe by some, and essential by others. Critics cite the safety conundrum created by a firearm that requires a magazine to be inserted in order to clear the trigger, increasing the chances of negligent discharge. Anecdotal law enforcement experience has praised the magazine disconnect in cases where they were disarmed by an attacker after having the magazine removed.
Other Safety Mechanisms
To adapt to a myriad of firearm handling preferences and requirements, firearm designers have devised mechanisms that defy simple classifications of external, internal, passive, or active. These systems serve the same purpose with equal or superior effect. Some actually predate many of the already-described mechanisms while others were developed to function in innovative ways.
Safety triggers are dual-piece triggers which require specific positioning and pressure to pull the trigger. If a piece of clothing or any other object snags one part of the trigger without activating both components, the trigger will not pull.
Double-action triggers cock the hammer, firing pin, or striker and release the firing device in a single stroke of the trigger. This trigger pull is long and heavy, requiring deliberate pressure from both the trigger finger and grip. If a double-action firearm is accidentally drawn from a holster from the trigger, the long, heavy trigger pull can prevent a double-action firearm from discharging (though this is heavily unadvised). With a double-action trigger, a deliberate trigger pull with an affirmative grip is required to fire a chambered cartridge.
For comparison, a single-action revolver requires the thumb to retract the hammer in order to rotate the cylinder and ready the hammer and trigger. Without the manual cycling action of the hammer, the trigger does nothing and a fresh round is not rotated into the breech. With a double-action revolver, a single trigger pull will rotate the cylinder, cock the hammer, and release the hammer upon firing.
Some semiautomatic firearms use a combination of single and double action trigger systems (DA/SA or Double-Action/Single-Action). Operation of the slide will load a round from the magazine and ready the hammer. With a retracted hammer, the trigger transitions into single-action mode, ready to release and ignite a cartridge.
The hammer can also be manually dropped onto the firing pin without igniting a cartridge. In this position, the trigger is in double-action mode, ready to cock and fire with a single pull of the trigger. While the double-action trigger itself works as a safety device, the process of dropping the hammer can be dangerous if the hammer slips and strikes the firing pin hard enough to cause an unintentional discharge.
A decocker is a safety device which drops the hammer while blocking or disengaging the firing pin. Once the hammer has been decocked, the pistol becomes a double-action pistol, requiring the long, deliberate pull to cock and release the hammer to fire.
A half-cock safety (please, hold your laughter) uses a specially-cut notch that holds a firearm’s hammer halfway between a cocked (readied) and decocked (dropped) position. In this position, the hammer does not rest on the firing pin. The primary purpose of a half-cock safety device is to allow safe loading of a firearm without the hammer being cocked and readied or resting on a round.
Half-cock safeties are typically only found on older firearms, and they are relatively fragile systems. They are prone to failure, and they do not necessarily prevent the hammer from falling when the trigger is pulled. Again, its main purpose is to permit safe loading of a firearm rather than act as a reliable safety mechanism to carry or transport a loaded firearm.
Manual Safety Devices vs Gun Safety
Manual safety devices are integral to some firearm designs, while they interfere with others. Any firearm on the market or a firearm that can be rented at a range has been designed with a wide range of safety features in mind, and only older firearms broker in compromises regarding built-in safety mechanisms.
Many people will only buy a firearm with an external manual safety, and they are entitled to this perceived peace of mind. There are many firearms which were designed to use a manual safety, and this feature will appeal to those who require it.
With that said, a firearm can be equipped with every possible safety mechanism described in this guide, and each is liable to malfunction, even if this possibility is statistically remote. All mechanical devices have limitations, and the greater the complexity, the greater the possibility of a catastrophic malfunction.
The only surefire safety is safe firearm handling. If one vigilantly exercises proper trigger discipline and follows the 4 Rules of Gun Safety, they can avoid negligent discharges while also reducing any potential damage caused by a statistically rare accidental discharge.
- Wikipedia Contributors. (2007, August 20). M1911 A1 pistol in .45 ACP by Remington. In Wikipedia, The Free Encyclopedia. Retrieved 12:00, June 28, 2019, from https://en.wikipedia.org/wiki/File:Bullet_coming_from_S%26W.jpg
- Wikipedia Contributors. (2009, March 23). Pistole SIG Sauer 226. In Wikipedia, The Free Encyclopedia. Retrieved 12:00, June 28, 2019, from https://commons.wikimedia.org/wiki/File:SIG_Sauer_P226_neu.jpg