This is a guest post by my author friend, William R. Bartlett. It continues his discussion of all things firearms. Part 1, Introduction, was published in late October. Today, Bill explains how semi-automatic handguns work and describes some common writing blunders. Enjoy and bookmark! 

A Writer’s Guide to Firearms by William R. Bartlett

Part 2: Semi-Automatic Handguns


A semi-automatic handgun will fire one round per trigger pull, providing there is ammunition. All semi-automatics have the ammunition stored in a magazine, usually removable and stored in the grip. These handguns range in size from barely larger than one’s palm and weighing less than a pound unloaded, to behemoths that weigh almost three pounds or more.


The parts of a semi-automatic handgun | From the blog of Nicholas C. Rossis, author of science fiction, the Pearseus epic fantasy series and children's book

Image: Encyclopedia Britannica

All have a barrel, a frame, which includes a trigger, a magazine, either fixed or removable, a trigger attached to a firing mechanism (which includes a manual safety), a method of extracting an empty case while putting a new round into the chamber, and sights for aiming the weapon. At one time, all of these parts were made from steel and made the weapon deceptively heavy, considering the size. Many modern handguns have a polymer frame which reduces the weight considerably.

The barrel, which includes the chamber, along with the trigger, firing mechanism, (usually, but not always, a hammer hitting a firing pin) and springs are always steel. Magazines can hold as few as five or six rounds or as many as a dozen. Many hold more. Some research may be in order for the writer to decide on a particular firearm and follow the constraints inherent in that weapon.

How it works

When the trigger is pulled on a chambered round with the safety off, it sets a chain of events into motion. In most cases, a hammer hits a firing pin, which hits the primer of the cartridge. The primer ignites the powder in the cartridge and propels the bullet forward. Consistent with Newtonian physics, the forward motion of the bullet starts a rearward motion of the handgun, but a spring keeps the slide forward until the bullet leaves the barrel and pressures drop to safe levels. At this point, the spring gives way and the slide travels rearward, re-cocking the hammer and ejecting empty casing. When the slide travels as far back as it can go, the compressed spring forces the slide forward. The slide strips another cartridge from the magazine and places it into the chamber. The weapon is now ready to fire again. This happens too fast for the eye to see.

When the last round in the magazine is fired, the slide locks in an open position. This does two things. It tells the operator that the ammunition supply in the magazine is depleted and the locked slide leaves the weapon ready to chamber a new round when the empty magazine is extracted and a full magazine is inserted. The operator need only depress a small lever and the released slide will chamber a new round. Incidentally, whenever a round is chambered and the weapon is ready to shoot, it is referred to as being in battery.

Some firearms manufacturers opt to simplify the hammer/firing pin arrangement and use what is called a striker. The striker is just a spring-loaded firing pin. The trigger is pulled and the striker is released to hit the primer on the cartridge. This means that there is no external hammer on the gun. With an external hammer, the operator can lower the hammer so gently as to prevent the weapon from firing. When the weapon is needed, the external hammer can be pulled back and the weapon can fire normally. This cannot be done with a striker. The only way to release the striker without firing is to pull the trigger without any ammunition in the piece.


Since the vast majority of semi-automatic handguns have a slide and the magazine is inserted through the bottom of the grip, that’s the only one I’ll discuss. Just remember, there are exceptions. To shoot a semi-automatic pistol, insert a loaded magazine through the bottom of the grip. Pull the slide all the way back and release it. This is frequently called ‘racking a round,’ or simply ‘racking.’ The weapon is now in battery. Align the sights on the target and squeeze the trigger. The weapon will automatically eject the spent cartridge and chamber another, enabling the piece to fire again. When the last round in the magazine is fired, the slide will stay open. Depress the slide release lever, and the slide will close. If the pistol has an external hammer, it can be lowered. If the weapon is striker fired, the trigger must be pulled to release spring tension on the striker.

There are several safety mechanisms on a semi-automatic handgun. Some have a hammer block, some block the trigger, some are integral with the grip, and some manufacturers incorporate several. Whatever method is used, it’s important to remember that these are mechanical designs and, although nearly always reliable, they are subject to mechanical failure, especially if the weapon isn’t used as designed. Dropping a handgun, for example, can result in an unintended discharge.


These weapons can have a magazine capacity exceeding a dozen rounds. They are usually more accurate since the chamber and the barrel are one integral unit. Felt recoil is lessened because the operation of the weapon absorbs some of the recoil. Reloading is as simple as ejecting the empty magazine and inserting a full magazine.


Because semi-automatics have more moving parts, there is a greater chance of failure. Springs can lose their strength if kept under tension for too long. Jams can take some time to clear. Loading magazines is more difficult because each cartridge has to be inserted against the pressure of the magazine spring. Most semi-automatics with a slide can be rendered inoperative by pushing on the slide at the muzzle, which takes the weapon out of battery. This is extremely dangerous because a character has to be touching the muzzle in order to affect the maneuver. However, if a character is that close, they may have nothing to lose with the attempt.

Writing failures

Many times, a reader’s willing suspension of disbelief can be lost when a writer makes simple errors about semi-automatic weapons. Here are a few:

  • Inserting a weapon into any waistband. Sweat suits, fleece pants, pajama bottoms all have a waistband designed for relaxation. These weapons are too heavy for the light elastic in garments of this ilk to hold the weapon safely. A holster on a belt, either threaded through slots or clipped on, is always the safest way to carry a semi-automatic handgun.
  • Failure to chamber a round. These weapons are typically stored empty until they’re needed. Inserting a loaded magazine will not make the weapon discharge with a trigger pull. A round must be racked into the chamber before the handgun will shoot.
  • Failure to reload. Even though a magazine can hold a large number of cartridges, the magazine can be depleted. At this time, the shooter will have to eject the empty magazine, insert another magazine, and depress the slide release button before shooting again.
  • Failure to sight on the target. The sights are deceptively simple. A blade front sight is aligned in a notch rear sight and both are aligned on the target. Even at close range, a target can be difficult to hit.
  • Failure to account for the noise. The sound of the gunshot can result in hearing damage if fired within closed spaces.


Mauser C-96 | From the blog of Nicholas C. Rossis, author of science fiction, the Pearseus epic fantasy series and children's book

A Mauser C-96. Source:

Some magazines are fixed and cannot be removed, as in the case of the Mauser C-96. The ‘Broomhandle,’ as it’s commonly known, is loaded from the top, using a stripper clip. The Luger doesn’t use a slide, it has a toggle on the top that was designed to work like the human knee. A Ruger handgun in .22 caliber has no slide. Instead, it has a charging handle at the rear and uses a bolt not unlike a small caliber rifle. There are some other handguns with the magazine located forward of the trigger, but not many. The far more popular design is where the magazine is located in the grip. Most likely, there are other exceptions of which I’m not aware.

I hope this helps with your writing. The next installment will cover revolvers.


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