“Gun companies make a big deal out of their handguns being drop safe,” RF said while puffing on a cigar (just before he quit, descending into madness). “Aren’t all modern guns drop safe? What does that mean, anyway?” The simple answer is no, not all firearms are “drop safe,” and that’s something designers have been trying to fix for centuries.
There are two ways that a firearm can discharge accidentally when dropped:
– An impact causes the sear (within the fire control mechanism) to disengage allowing the hammer or striker to fall and start the firing process — just as if someone had pressed the trigger,
– An impact on a cartridge-based firearm with a free floating firing pin causes the firing pin to move forward and strike the cartridge’s primer with sufficient force to ignite the primer.
Neither of these possibilities are desirable. But addressing the issue has taken centuries . . .
The earliest firearms had no safeties; partly because they were inherently unreliable. When firearms technology advanced to flintlock designs in the 1600’s, the mechanism was reliable enough to introduce safety mechanisms.
The first such safety: a “half cocked” position on the firearm’s hammer. This position allowed the user to carry the weapon loaded and primed; the trigger wouldn’t function until the hammer was pulled all the way back to the “full cock” position.
The idea of that a firearm should be “drop safe” entered the public consciousness when cartridge-based firearms became popular, during the late 1800s. As the new weapons could be loaded well ahead of firing (without reliability issue), more and more people started carrying handguns on a daily basis.
Gun owners worried that a dropped firearm could accidentally discharge and injure or kill an innocent bystander. Hunters and the military had additional concerns: a dropped firearm that discharged could scare off game or alert the enemy to the gun owner’s position.
Single action revolvers and lever action rifles were the first firearms to implement a “drop safe” design. They exploited the same mechanism that had been used for centuries: a “half cocked” position on the hammer. Since the shooter had to manually cycle the firearm’s action for every round, this was a logical “leap.”
When semi-automatic and fully automatic firearms started appearing in the early 1900’s, the “drop safe” landscape changed. As the user didn’t need to pull back the hammer for every shot, gunmakers needed a different safety system.
Engineers like John Pedersen decided that “double action only” handguns were the solution. If the hammer wasn’t under tension and poised to fire, there couldn’t be an accidental discharge even if the sear was released.
For his 1911 design, John Moses Browning used a traditional “half cock” position. He added a grip safety and manual safety to make sure that the gun only fired when the user was really, really ready. A spring-loaded firing pin completed the design, ensuring that even if the gun was dropped the firing pin wouldn’t hit the primer with enough force to ignite.
As machining processes improved, another safety mechanism became popular: the firing pin safety.
Gun designers created a small pin to lock the firing pin in place, keeping it from moving. That pin only moved out of position when the trigger was pressed. At that point a small lever pushes the pin out of the way, clearing the firing pin channel, allowing it to move.
There was only one issue: the pin was held in position by a spring. If a gun was dropped in just the “right” way, the firing pin safety could move out of position via its own momentum (as the rest of the gun abruptly stopped). But, as there were multiple mechanisms preventing the gun from firing, this wasn’t considered an issue.
When striker-fired handguns hit the scene in the 1980’s, hammer-related safety devices were no longer viable.
When a striker-fired gun’s slide moves forward, it pulls back the spring controlling the striker. This puts the firing pin — which strikes the primer directly — under spring tension. The “cocking” process created by the slide’s movement serves the same function as moving a hammer back on a double action firearm — storing energy until the hammer or firing pin is released.
To ensure that a striker-fired gun doesn’t discharge when dropped, designers rely heavily on the firing pin safety. Which can fail. So they usually build in another safety feature: the movement of the slide doesn’t cock the striker all the way back. Only 70% to 90% of the energy required to ignite the primer on a cartridge is stored from the movement of the action, the rest is provided by the shooter when they pull the trigger.
The movement of the trigger adds the remaining energy needed which finally trips the sear, releasing the striker, and igniting the primer. Safety conscious designers usually opt for loading on the lower end of the scale, believing that it will reduce the possibility that the under powered striker will ignite the primer if the sear trips and the firing pin safety fails. Others load to the higher end, opting for a shorter trigger pull and crisper break.
Bottom line: not all firearms are “drop safe.”
Certain states like California require all firearms to be certified drop safe according to their own test protocols. But there’s no legal requirement otherwise in the United States for guns to be drop safe. Typically, all modern handguns will not accidentally discharge if dropped from the average height of a human’s hand.
Some are rated from even greater heights, while some aren’t “drop safe” at all. The 1911 series of handguns, for example, aren’t considered to be “drop safe” without modifications (such as the inclusion of a firing pin safety). A number of Taurus handguns also fall into this category, along with other lower quality and lower-priced firearms.
While “drop safety” isn’t required for civilian ownership in some jurisdictions, it’s often a requirement for military contracts and law enforcement professionals, whose employees and agents will often be in dynamic situations (e.g., parachuting out of airplanes, fast roping out of helicopters, and wrestling with suspected criminals).
Whether or not your gun is drop safe, it’s best not to drop it. And never try to catch a falling gun.