In 1830, when he was only 16, Samuel Colt left home and
took a job on a merchant ship bound for India. In his spare
time, he toyed with designs for a new sort of gun -- one that
could be fired repeatedly without reloading. While a number of
repeating weapons had already been developed, none of them had
caught on with the public, mostly because they were too
complicated and cumbersome.
by a capstan
mechanism on the ship, Colt developed a simple revolving
ammunition cylinder. Initially, people weren't
particularly impressed with the new weapon; but by the 1850s,
Colt's company was enjoying phenomenal success. In 1856, he
had to churn out 150 guns a day just to keep up with the
The extremely simple, highly reliable weapon had a profound
effect on life in the United States and later in the rest of
the world. Armed with a revolver, anybody could kill another
person in a matter of seconds. War, crime, law enforcement and
even everyday arguments were infused with a new deadly
In this edition of HowStuffWorks,
we'll look at the basic operating principle of the revolver to
see why it remains such a popular weapon after more than 150
years on the market. We'll also look at the basic concepts
behind firearms and check out a few of the important weapons
that preceded the revolver.
Gun Basics and History
To understand how a
revolver works, it helps to know something about guns in
general. Almost every gun is based on the same simple concept:
You apply explosive pressure behind a projectile to launch it
down a barrel. The earliest and simplest application of this
idea is the cannon.
A cannon is just a metal tube with a closed end and
an open end. The closed end has a small fuse hole. To load the
cannon, you pour in gunpowder (a mixture of charcoal, sulfur
and potassium nitrate), and then drop in a cannonball. The
gunpowder and cannonball sit in the breech, the rear
part of the bore (the open space in the cannon). To
prepare for a shot, you run a fuse (a length of flammable
material) through the hole so it reaches down to the
gunpowder. To fire the cannon, you light the fuse. The flame
travels along the fuse and finally reaches the gunpowder.
When you ignite gunpowder, it burns rapidly, producing a
lot of hot gas in the process. The hot gas applies much
greater pressure on the powder side of the cannonball than the
air in the atmosphere applies on the other side. This propels
the cannonball out of the gun at high speed.
The first handheld guns were essentially miniature cannons;
you loaded some gunpowder and a steel ball and lit a fuse.
Eventually, this technology gave way to trigger-activated
weapons, such as the flintlock
gun and the percussion
A percussion-cap gun (left) and a flintlock
gun (right), two important steps on the way to modern
Flintlock guns ignited gun powder by producing a tiny
spark, while percussion caps used mercuric fulminate,
an explosive compound you could ignite with a sharp blow. To
load a percussion-cap gun, you poured gunpowder into the
breech, stuffed a ball in on top of it, and placed a mercuric
fulminate cap on top of a small nipple. To fire the gun, you
cocked a hammer all the way back and pulled the gun's trigger.
The trigger released the hammer, which swung forward onto the
explosive cap. The cap ignited, shooting a small flame down a
tube to the gunpowder. The gunpowder exploded, launching the
ball out of the barrel. (Check out How
Flintlock Guns Work for more information on these
In the 1800s, the percussion-cap gun slowly gave way to the
revolver, which only had to be reloaded every five or six
shots instead of after each shot. In the next section, we'll
see how this system works.
The first revolvers used
gunpowder, balls and caps like the earlier percussion-cap
pistols. The shooter would load each of the six chambers in
the cylinder with gunpowder and a projectile, and place
separate percussion caps on corresponding nipples. While the
loading procedure was tedious, a shooter could have six rounds
fully prepared ahead of time.
In the 1870s, these models were replaced by revolvers that
used bullet cartridges instead of gunpowder and caps.
Cartridges are a combination of a projectile (the bullet), a
propellant (gunpowder, for example) and a primer (the
explosive cap), all contained in one metal package.
In a modern revolver, cartridges are loaded into six
chambers, each of which can be positioned in front of the
gun's barrel. A spring-loaded hammer is positioned on the
other side of the cylinder, in line with the barrel. The basic
idea of the gun is to cock the hammer back, line up a new
cartridge in between the hammer and the barrel and then
release the hammer by pulling a trigger. The spring throws the
hammer forward so it hits the primer. The primer explodes,
igniting the propellant, which drives the bullet down the
The inside of the barrel is lined with spiraling
grooves, which spin the bullet to give it stability. A
longer barrel improves stability, since it spins the bullet
for longer. Extending the barrel also increases the speed of
the bullet, since the gas pressure accelerates the bullet for
a longer period of time.
In early revolvers, a shooter had to pull the hammer back
before each shot and then pull the trigger to release the
hammer. In modern revolvers, simply pulling the trigger will
force the hammer backward and then release it.
You can see how a modern revolver works in the diagram
Obviously, a revolver is easier to use than a flintlock or
a percussion-cap weapon. A shooter can load six shots at a
time and only needs to pull the trigger to fire. But revolvers
seem very limited next to newer technologies: The shooter must
pull the trigger for every shot and stop to reload regularly.
On the battlefield, the revolver can't possibly stand up to
For more information on revolvers and other weapons, check
out the links on the next page.