Firearm Terminology Explained

As the eye-opening new documentary series Battle Factory comes to Yesterday, here’s a guide to some of the often surprising technical jargon of firearms.

Battle Factory: Firearm Terminology Explained


Most of us know them as silencers, but firearms users tend to call these pieces of kit suppressors. That's because, contrary to what Hollywood shows, suppressors do not turn loud bangs into subtle little "ptub-ptub" sounds.

The inside of a suppressor

The inside of a suppressor

Bear in mind the average gunshot can be around 150 decibels, which is louder than a jet engine and can permanently damage your hearing in an instant. A suppressor can knock this down by around 20 or 30 decibels - still remaining very, very loud. Suppressors contain hollow chambers, which allow the propellant gas from a fired cartridge to escape at a lower velocity, which reduces the noise.

There's still the matter of the "ballistic crack", though. That's the sonic boom a bullet makes as it breaks the sound barrier.

No suppressor can reduce the ballistic crack, but "subsonic" ammunition does exist, where the bullets are designed to travel at just less than the speed of sound. Using these together with suppressors will make the firing of a gun even quieter, but still a far cry from the near-silent hitmen weapons you see in films.


"Rifling" is the term for the twisting grooves carved inside the barrel of the gun. Anyone who's seen the opening James Bond sequences will know what rifling looks like.

The spiralled rifling of a gun barrel

The spiralled rifling of a gun barrel

However, it's not just rifles that are rifled. Pretty much all firearms are, with the notable exception of shotguns.

Hundreds of years ago, the smoothbore barrels of muskets were the norm. These fired tiny balls with very little accuracy by today's standards. Rifling was a huge evolutionary leap, as the spiral grooves give a spin to the projectile, making it more stable in the air and easier to aim. It's basically the same principal as a spinning rugby ball.

Meanwhile, the vast majority of shotguns are smoothbore because they fire cartridges filled with pellets, and a rifled barrel would make these explode out in a wider, less accurate formation.


Despite what many people assume, blanks can in fact be deadly. That's because a blank cartridge still contains gunpowder and paper or plastic wadding - it just lacks the bullet element.

When the trigger is pulled, the gunpowder ignites, releasing the wadding along with all the intensely expanding hot gas of a regular cartridge blast.

In other words, a blank can easily cause serious injury or even death if the gun happens to be pressed up against a body when fired.

Perhaps the most notorious example of such an accident happened in the 1980s, when TV actor Jon-Erik Hexum died on set after jokingly putting a gun loaded with blanks against his own temple and pulling the trigger.

Calibre and Gauge

You've heard the word used countless times, but what exactly is a "calibre"?

Very simply, calibre is a measurement of the diameter of the ammunition in question, or the internal diameter of the gun barrel. Calibre can be expressed in millimetres or in hundredths of an inch - for example, a .45 is 45/100ths of an inch.

Shotguns are measured in "gauges" - a very old fashioned system based on how many lead balls of the diameter of that particular shotgun barrel you could make from one pound of lead. For example, you could make 12 correctly-sized balls for a 12-gauge shotgun. So, generally speaking, the higher the gauge, the smaller the shotgun.

For more on the world's weaponry and combat gear, and to discover how they're really made, catch Battle Factory on Yesterday.