Tuesday, January 22, 2013

Just the Basics - Hammers and Strikers


All cartridges fired from handguns, long guns or shotguns are fired by having their primer sharply struck by a firing pin. The mechanics to make this happen have boiled down into two primary configurations – the Hammer Fired or the Striker Fired firearm.

During a recent class, as I was going over this detail, eyes glazed over and I realized I had lost them and had no readily accessible images to explain this difference. I also suspect that if the folks I had in the classroom that day had questions, other folks might as well. So, let’s chat a bit about “Hammers and Strikers”.

Let’s start with one of the earliest and simplest hammer fired weapons, the .45 Single Action Revolver.

The Hammer is found on the rear of the weapon. It has 4 positions:

Fully Forward: The Hammer is fully forward, the Firing Pin if fully in and slightly through the Hammer Port – meaning it rests mere millimeters from the face of the primer of the cartridge that is in the firing position. Perhaps not the safest configuration.

“Safety” Position: The Safety Position in one-click back. In this position, the cylinder is locked, the Nose of the Hammer is withdrawn into the Hammer Port, the Trigger is locked and the firearm is much safer in the event in is dropped. For a modern, single action revolver, this would be the safest way to cary the handgun – with the exception of leaving the firing chamber empty.

Half Cocked: Half Cocked is two clicks back and allows the cylinder to spin freely. This is the Hammer position used to both load and unload the firearm via the Loading Gate.

Fully Cocked: The Hammer is three clicks back and the weapon is fully ready to fire. In this particular SA Revolver – less than a pound of pressure with my trigger press will release the hammer and fire the weapon.

The Hammer strikes the primer by plunging through the Hammer Port. This strike ignites the primer which ignites the powder within the cartridge firing the bullet down the barrel and out of the muzzle of the firearm.

The Firing Pin is Integral to the Hammer meaning that it is a physical part of the hammer. The very end of the Firing Pin – that part that actually strikes the primer is called the Nose.

45cal SA Hammer - Firing Pin - Firing Pin Port

The Single Action revolver evolved into a Double Action Revolver. This meant that by simply pressing the trigger the Hammer was cocked, the cylinder was rotated and finally the Hammer was released – firing the weapon. With this change came some changes in the design of the Firing Pin.

The Firing Pin became part of the frame. The Firing Pin Nose can be seen on the inside of the weapon when the cylinder is rolled open. The rear of the Firing Pin is available to the struck by the Hammer Face.

Notice that the Hammer has a Transfer Bar Notch – this provides a space for the Transfer Bar. This space provides a place for the Transfer Bar to rest with the Hammer is fully forward. The insertion of this bar insures that the space between the Nose of the Firing Pin and the Primmer is fixed, insuring that the firearm will not fire should the weapon drop. When the trigger is pressed, the Transfer Bar is shifted and the Hammer Face strikes the rear of the Firing Pin discharging the weapon.

Tarus DA Hammer-Strike Face-Firing Pin

The move to semi-automatic pistols again required a change in the design of the Firing Pin. This Springfield 1911 is a good example of the Hammer fired semi-automatic pistol.

The Firing Pin extends slightly out of the rear of the weapon. It is pushed out by the Firing Pin Spring. When the trigger is pressed the Hammer is released and strikes the rear of the Firing Pin – driving it into the primer and discharging the weapon.

Notice that the Firing Pin is slim and tapered. The Firing Pin Spring is what insures that rear of the Firing Pin is exposed through the hole in the Firing Pin Stop. The Firing Pin Spring is one of the components that may need to be replaced over time as it weakens and the weapon begins to experience “light strikes”.

The Extractor rides down the slide along the inner edge to slip behind the lip of the .45cal ACP cartridge. As the slide moves to the rear it extracts the spent casing from the chamber and ejects it out of the side of the weapon through the ejection port.

Note that the Firing Pin is a fairly slender, smallish bit of hardware. This is one of the things that set it apart from a Striker where the Striker is the Firing Pin – as in the Glock 36 pistol shown next.

1911 - Hammer and Strike Face

This Glock 36 provides a good example of a Striker Fired firearm. The first thing you notice is that the Firing Pin is significantly “beefier”. There is more bulk and mass to the pin. You can also see that the same goes for the Firing Pin Spring. It is this combination – the size and mass of the Firing Pin and the strength of the Firing Pin Spring that will send this Firing Pin – the “Striker” - into the primer, discharging the weapon. There is a Firing Pin Spacer on the rear of the Firing Pin that helps to center the Firing Pin in its channel. The Firing Pin Nose will extend through the channel to strike the primer, discharging the weapon.

Glock Rear Slide and Firing Pin

Hammers – Firing Pins – Strikers . . . . they all get us to the same place. They make your firearm go BLAMMMMMM!! Yet, there are important differences.

As in all things – words matter.

And now you know that they mean . . . .


  1. And always load SAAs one round short and put the hammer down on the empty chamber... :-)

    1. Yep, unless you want a real surprise one day . . . . :)