Can The Safety On A Gun Fail? It Absolutely Can
Can the safety on a gun fail? It absolutely can, which is why safe handling and carrying of a firearm is vitally important. Everything mechanical has a failure rate, so it behooves you to bear these things in mind.
There are a number of forms of mechanical safety devices on firearms, all of which are susceptible in some way to a failure and thus the potential of a mishap of some sort.
If you understand the nature of those safety devices, as well as their vulnerabilities, that can inform you of what you need to do in order to carry, handle and shoot guns safely. Remember, gun safety is all on you; it's your responsibility to be safe with them.
We'll briefly touch on how mechanical safety devices work, what can cause them to malfunction in various situations, and how you address them to stay safe.
Drop Safety: Hammer And/Or Firing Pin Blocks
One of the most common safety devices on a gun is the drop safety system. In all cases, it's a mechanical block that keeps the firing pin, hammer or striker/firing pin from impacting the primer of a chambered cartridge unless the trigger is pulled.
There are two dominant forms.
The oldest form is a transfer bar safety, which is installed on basically all modern revolvers except for reproductions of single-action revolvers from the 19th century such as those by Uberti, Pietta, and Colt.
A transfer bar is a tilting piece of metal hinged to the trigger. When the trigger is at rest, the transfer bar slides up into the hammer channel and blocks it from striking the firing pin or - in the case of revolvers without one - the cartridge itself.
The transfer bar safety only drops out of the way if the trigger is pulled.
Semi-auto pistols typically use a firing pin block, likewise mechanically linked to the trigger.
The typical design is a piece of metal - typically a cylinder - with a cutout. When at rest, the firing pin block acts as a wedge, preventing any travel of the firing pin block. When the trigger is pressed, the firing pin block is lifted, allowing the firing pin to travel and strike a cartridge.
There are some exceptions, however, such as the Walther PPK, but most modern production semi-autos use a lifting firing pin block.
Drop Safe? Only Up To A Point
Modern handguns are designed to be drop-safe, using the mechanical system above.
Another factor in the favor of safety is sheer physics and the firing pin itself.
For a pistol with a firing pin to discharge, the firing pin has to be struck with enough force to slam it into the primer of the cartridge in the chamber.
A dropped gun is that it hits the ground with enough force to do that, but the issue is how much of that force is absorbed by what part of the gun. In order for a discharge to happen, sufficient force has to be directed into the firing pin itself to cause it to slam forward.
However, this happens when the gun is dropped either directly onto the back of the slide, or the back of the slide at the correct angle.
Gun companies do their best to make sure their products are drop-safe. However, they can't anticipate every angle a pistol may fall at, the heights from which it may fall, material it might fall on, or all of the hundreds of variables in the equation.
The term here is "reasonable precautions," which is certainly what they take to ensure their products are drop safe...but that doesn't mean there aren't conditions under which a drop fire can happen.