The motion often seen in films where a character, after pointing a gun, twists a “switch” on the back of the pistol with their palm is mostly used for dramatic effect. That “switch” is actually the gun’s hammer, and cocking it aims to show that the character is serious about pulling the trigger. However, this action can be a cliché carried over from western films — especially on modern firearms, Hollywood often gets the technical details wrong.
What is a switch on a gun?
The piece that appears as a “switch” in films is technically called the hammer (or cock). In hammer-fired guns, together with the firing pin, it is the critical part that causes the cartridge to fire.
How does the hammer work?
In general terms, the hammer is under tension from a spring called the mainspring. When the trigger is pulled, the hammer is released from that tension and quickly swings forward. With that motion it strikes the rear of the firing pin. The firing pin then transfers that energy to the primer — the part at the back of the ammunition cartridge. The primer ignites, the powder burns, gas pressure builds, and the bullet is forced out of the barrel.
Is it necessary to cock the hammer by hand?
The answer depends on the firearm’s design. Not all guns operate this way; some have the hammer hidden or use a different mechanism such as striker-fired systems. Hammer systems are generally divided into two types:
- Single Action (SA): In these systems, the hammer must be cocked (pulled back) before the trigger can be pulled. Many of the revolvers seen in westerns are this type, and they require manually cocking the hammer. On some pistols like the 1911, the slide’s movement automatically cocks the hammer.
- Double Action (DA): In these firearms, pulling the trigger both cocks the hammer and — if continued — releases it to fire. Therefore, on DA guns it is not necessary to cock the hammer by hand.
Why is it used in films?
Cocking the hammer by hand is most often used in films to create dramatic effect. The motion signals that the gun is now ready to fire and reinforces the idea that the character is serious about pulling the trigger.
From a technical perspective (especially with double-action firearms), cocking the hammer makes the trigger pull lighter (requires less force), which reinforces the shooter’s intent. However, Hollywood frequently misrepresents these technical details (for example, adding hammer sounds to striker-fired pistols like Glocks that do not have an external hammer), and it should be noted that this action is, in many modern firearms, mostly an unnecessary cliché.