A quick walk through a well-stocked gun shop with today’s revolvers and semi-auto pistols might seem daunting. However, a mental dash through firearms history will help sort things out.

Let’s go back to the 1100s, when the first man-portable “firearms” were invented. After the Chinese discovered gunpowder, it didn’t take long for them to determine that stuffing some of it in a bamboo tube, topping it with rocks and igniting it would throw the projectiles farther and faster than human power could accomplish. Fast-forward to the mid-19th century, when mankind had refined firearms. But they were still essentially stuffing rocks down tubes on top of a charge of black powder and igniting it.

19th Century

Samuel Colt patented the revolving (and repeating) pistol in 1836, while his competitors Horace Smith and Daniel Wesson bought the rights for a “bored-through” revolving cylinder for a pistol from Rollin White to go with their patent on self-contained ammunition cartridges. By 1856, when Colt’s patent expired, Smith and Wesson’s timely launch of Volcanic Repeating Arms in 1852, and its subsequent sale to Oliver Winchester in 1855, financed the iconic revolver company that bore the names of the men.

As firearms patents expired, other gun companies sprang up and kept improving technology, metallurgy and chemistry. This ultimately resulted in today’s revolver.

Not satisfied with the six shots offered by most revolvers, Hugo Borchardt patented his C93 self-loading pistol with some help from his assistant Georg Luger. However, Borchardt’s ego got in the way of making changes to his design—the first mass-produced, magazine-fed, self-loading pistol—so the German military asked Luger to make some changes. He obliged, and by 1908, the iconic P-08 Luger, firing the 9x19mm Luger cartridge, was born.

America’s most prolific firearms inventor, John Moses Browning, patented his first firearm design in 1885. His discovery of the waste of burning powder gases led to his self-loading automatic machine gun designs. This quickly developed into semi-automatic pistol designs by 1899. His designs continued to improve, but his initial design—which incorporated a barrel surrounded by a shroud, creating the first pistol “slide”—is still the primary one used in most recoil-operated semi-auto pistol designs today. Browning also produced some of the most popular pistol cartridges still in use, including the .25 ACP, .32 ACP, .380 ACP and .45 ACP.

Today’s Handguns

Three basic pistol designs exist today: the revolver, semi-auto and the less common breechloader with one or more barrels. Because revolvers and semi-autos make up most handgun sales, we’ll dissect those to better understand their attributes. Understanding how pistols work will give you a deeper knowledge of how to handle them safely and effectively.

When a gun fires, the primer ignites the powder charge, and the burning/expanding gas pressure drives the bullet down the barrel. The rifling puts a spin on the bullet, which keeps the bullet pointed in the same direction during flight, increasing accuracy. Rifling consists of spiral cuts in the bore. The raised parts of the rifling are called grooves, and the lands are the ridges of metal between the grooves.

“Caliber” describes the size of a handgun bore and the size of the bullets designed for various bores. Caliber is usually measured as the diameter of the lands in the bore and expressed in hundredths of an inch, thousandths of an inch or millimeters. For example, a .357-caliber handgun bore measures 0.357 inches in diameter. There are no standards established for designating caliber, which can make things confusing. In some cases, caliber is given as the diameter of the bullet or something close in size to the bore diameter or bullet diameter.

However, every pistol is designed to fire a specific cartridge. Be sure that the ammunition matches the data stamp on the firearm, and follow the manufacturer’s specifications regarding power rating. For example, some sturdier pistols can fire +P ammunition, which is loaded for more power. Lesser designs can’t handle this more powerful ammunition without damaging the gun.

Basic Components

All modern handguns have three basic groups of parts: trigger group, frame and barrel.

The trigger group contains the component parts that fire the cartridges. The frame is a metal housing that might also serve as the handle (grip) of the handgun. It contains the trigger group. The barrel is the metal tube through which the bullet travels. Of course, a handgun barrel is much shorter than a rifle or shotgun barrel because the gun is designed to be shot while being held with one or two hands rather than being placed against the shooter’s shoulder. The term “action” can describe the function of the weapon, or as a noun, describe the specific part of a gun.

Repeating handguns (revolvers and semi-autos) hold more than one round of ammunition. A revolver uses a cylinder to store the ammunition, while a semi-automatic pistol uses a removable magazine inserted into the grip.

The term “pistol” is another point of confusion. Some assert that it describes the action type—that is, a distinction between the terms pistol and revolver—maintaining they are two handgun types. To clear things up, the term pistol describes any weapon designed to be fired with one hand. The word “pistol” is the primary handgun category, with revolvers being a descriptive subset of pistols.


The best way to delve into learning about revolvers is to start with “single-action” models. This revolver is the earliest design that required the shooter to manually cock a hammer before pulling the trigger. After firing each shot, users must manually cock the hammer, which makes the cylinder rotate and place an unfired cartridge in line with the barrel to ready it for discharge with a subsequent shot. When all rounds are fired, the loading gate is opened, revealing a spent cartridge case. The empty case is forced from the cylinder by an ejector rod, and the cylinder is rotated by hand to expose the next empty cartridge. The process is repeated until all cylinders are empty. New cartridges are inserted into each empty chamber in the cylinder until all are filled to ready the gun to fire again.

The “double-action” revolver is similar but adds a second method of firing. In double-action mode, the trigger rotates the cylinder, cocks the hammer, releases the hammer. Because double-action mode requires more mechanical work to operate the pistol, it requires more trigger-finger force to fire the gun. Some double-action-only revolvers have hidden hammers and only fire in that second mode.

Semi-Auto Pistols

Self-loading pistols share many common features, typically including reciprocating slides that move back and forth while the barrel stays relatively motionless. The travel of the slide chambers cartridges from the magazine and extracts loaded cartridges or fired cases from the chamber.

Some of the earliest self-loading pistol designs have magazines that don’t detach from the gun, such as the Mauser C96. Most modern self-loading pistols use a detachable magazine, however. This allows users to carry several preloaded magazines for rapid reloading. Semi-auto pistols with detachable magazines incorporate a latch, button or lever that releases the magazine so it can be removed. Two of the primary advantages of self-loading pistols over revolvers are the speed of reloading and the increased ammunition capacity.

All firearms have an action type, which is the group of moving parts that control the firing and operation. Semi-auto pistols also incorporate several action types, including single-action, double-action, striker-fired, double-action-only and double-action/single-action. Those are the most common action types, although some might expand the list.

A novice might conclude that double-action means a gun can shoot two ways, or make similar assumptions about other action types. The simplest way to determine the action type is to see how many actions occur when the trigger is pulled. If the trigger only releases a pre-cocked hammer, the gun is a single action. But, if pulling the trigger simultaneously draws the hammer to the rear and releases it, firing the gun, it’s a double action. However, if both actions are possible—cocking the hammer manually or pulling the trigger and drawing the hammer to the rear—it’s a double-action/single-action.

Internal striker-fired pistols are the most modern designs. The firing pin is partially cocked when the slide is drawn back, and it’s fully cocked and released when the trigger is pulled.


Manual safeties on self-loading pistols can take several forms. Some pistols incorporate multiple safeties, but others only use a passive two-part lever embedded in the trigger. The oldest safety designs include a lever on the rear of the frame or slide. Additionally, some safety levers act as decocking devices, too.

Grip safeties can also be part of the design, whereby the shooter has to squeeze the grip to depress the safety before firing. The Colt Model 1911 has a grip safety as one of its three safety mechanisms. The others are the thumb safety and the hammer itself, which must be cocked before firing.

A cautionary note about safeties: Some models include a key-lock safety to prevent unauthorized people from firing the pistol. These can malfunction from the wear of firing and leave the owner with a gun that won’t work. Additionally, some models incorporate an internal safety that gets engaged when the magazine is removed. The downside to that design is it typically makes the trigger press harder and less smooth.

This article was originally published in Personal Defense World, Gun Primer 2018. To order a copy, please visit

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