Safety (firearms)
In firearms, a safety or safety catch is a mechanism used to help prevent the accidental discharge of a firearm, helping to ensure safer handling.
Safeties can generally be categorized as either internal safeties and external safeties. Sometimes these are called "passive" and "active" safeties, respectively. External safeties typically work by preventing the trigger from being pulled or preventing the firing pin from striking the cartridge.
Firearms which allow the user to select various fire modes may have separate controls for safety and for mode selection or may have the safety integrated with the mode selector as a fire selector with positions for safe, semi-automatic, and fully automatic fire.
Some firearms manufactured after the late 1990s and early 2000s include a mandatory integral locking mechanisms that must be deactivated by a unique key before the gun can be fired. These integral locking mechanisms are intended as child-safety devices during unattended storage of the firearm—not as safety mechanisms while carrying. Other devices in this category are trigger locks, bore locks, and gun safes.
Typical safeties
Manual safety
The most common form of safety mechanism is a switch, button or lever that when set to the "safe" position, prevents the firing of a firearm. Manual safeties are as varied as the designs of firearms themselves, but the two most common mechanisms are a block or latch that prevents the trigger and/or firing mechanism from moving, and a device that disconnects the trigger from the firing mechanism of the firearm. Other designs may block the hammer or striker from forward movement or act as a block to prevent them from contacting the firing pin. In addition some manual safeties such as the Ruger SR9 pictured lock the pistol's slide closed when in Safe position whereas, for example, S&W M&P manual safeties do not lock the slide closed. The benefit of these design variances have not been clearly stated or pointed out by manufacturers, however, in the Ruger SR example, a chambered round cannot be ejected to empty the gun with the manual safety in the safe position. The safety must be OFF to clear the weapon. In the M&P design, the slide can be manually actuated and a chambered round ejected with the manual safety in safe position. One possible benefit of the slide-safety lock may be that, upon holstering, the slide cannot be snagged and hung up out of battery. Manual Safeties are the oldest forms of "active" safety mechanism and are widely used; however, many "double-action" firearms such as revolvers do not have manual safeties as the longer, harder trigger pull to cock and fire double-action provides adequate trigger safety, while keeping the firearm in a more ready state.Grip safety
A grip safety is a lever or other device situated on the grip of a firearm which must be actuated by the operator's hand, as a natural consequence of holding the firearm in a firing position, in order for the firearm to fire. It is usually similar to a manual safety in its function, but is momentary; the safety is deactivated only while the shooter maintains their hold on the grip, and is reactivated immediately once the shooter releases it. The M1911 design is a popular example of a handgun with a grip safety, while the Uzi submachine gun and the HS2000 and its descendants are other notable examples of this type of safety.A related grip-type safety is the decocking grip found on some H&K pistols like the P7 Series. The firearm is cocked and ready to fire only when the front of the grip is squeezed by the operator. When the grip is released, the firearm is decocked, and the single-action trigger will not cock the firearm, therefore it will not fire unless the grip is squeezed and the trigger pulled. Alternatively, the trigger can first be pulled and then it will fire when the grip is subsequently squeezed. Finally, if both the grip is squeezed and the trigger pulled simultaneously, the pistol will fire.
Another, unusual variant was found in the Ortgies semi-automatic pistols. To disengage the safety, a user would squeeze a lever until flush with the rear of the grip. The lever then would latch in the disengaged position until the user released it again by pressing a button under the slide, whereupon tension from the striker spring would push it back to the engaged position. Thus engaging the safety also relieved some tension in the striker spring. As the Ortgies is a pocket pistol meant for personal defense, this feature eliminates the problem of failing to disengage the safety when one needs to shoot. Gripping the pistol tightly is all it takes to disengage the safety.
Decocker
Most traditional semi-automatic double-action/single action pistols are designed to be carried with the hammer down on a chambered round, with or without a manual safety engaged. The pistol is considered safe in this state as the "double-action" pull that both cocks and fires the firearm is both longer and heavier than the "single-action" pull that simply releases the cocked hammer, and thus an inadvertent trigger pull is less likely.However, the act of cycling the action on such a firearm will leave the hammer cocked in single-action mode. To return the pistol to its safe state, it is necessary to uncock the hammer, usually by holding the hammer spur, carefully pulling the trigger, and then slowly lowering the hammer on the firing pin.
Hammer-fired semi-auto pistols have a beaver tail to protect the shooter's hand from the slide, which makes it more difficult to securely and firmly grasp the hammer with the thumb than a double action/single action revolver, thus making an accidental discharge more likely. Striker-fired pistols, on the other hand, do not have a hammer, so the only way to return the trigger to its longer pull state is by means of a decocking or detensioning lever which actually releases the tension in the striker's spring without allowing firing pin full travel and internal safeties disengagement.
When a handgun is fitted with a "decocking" lever, there is no need to pull the trigger while holding the lever like in a revolver. The actual process of "decocking" the gun is done by simply flipping the decocking lever to its "decocked" position with the fingers away from the trigger.
File:SIG P226 IMG 3053-labels.jpg|thumb|right|SIG Sauer P226 controls and parts: 1. Ejection port 2. Rear sight 3. Hammer, 4. Takedown lever 5. Decocker 6. Slide stop 7. Trigger 8. Magazine release
A decocker or manual decocking lever allows the hammer to be dropped on a live cartridge without risk of discharging it, usually by blocking the hammer or retracting or covering the firing pin before releasing the sear. That eliminates the need to pull the trigger or to control the fall of the hammer; however, since all mechanisms can fail, it is still necessary to keep the muzzle of the gun pointed in a safe direction while decocking.
A decock/safety is a combination manual safety switch and decocking lever. Two popular variants exist. In the "three-way" system, made popular by Heckler & Koch pistols, the handler may decock the firearm by pushing down on the safety lever from the "Fire" setting, or engage the safety by pushing the lever upwards. A simpler "two-way" system was popularized by the Walther PP and is also commonly seen on the Beretta 92: engaging the safety also decocks the firearm.
The SIG Sauer line of pistols, such as the SIG P226, frequently feature decocking levers. The earliest use of a single-action decocker was the Vis wz. 35 "Radom" redesign in 1932 to enable horsemen to safely holster their firearm with one hand. The earliest use of a cocking/decocking lever is the Sauer 38H from 1938. Ruger until 2007 manufactured "decock-only" variants of its P-series pistols, and the "two-way" decocking safety has been available on these pistols since their introduction.