Picture this: You’re in the heat of battle, holed up in an abandoned building for cover as
bullets whizz and ricochet around you. Enemies are closing in on all sides.
You’re outnumbered and outgunned. Your primary weapon - an assault rifle, naturally - is spent.
You’re just down to your sidearm now, a 9mm pistol. You’re ready for your last stand.
They breach the door. You can hear the enemy coming. You draw a bead on the approaching
combatants and squeeze the trigger - but, in the crucial moment, your weapon jams.
For a second, it looks like it’s all over, but then you remember:
You’ve got one more frag grenade fixed to your belt. You grab it, and like a movie action hero,
you make the inadvisable decision to pull out the pin with your teeth. Dental work aside,
you toss the grenade into the crowd and jump for cover. Three, two, one...Boom.
Your trusty frag grenade has saved the day. After all, a numerical advantage doesn’t really matter
when you get blown to kingdom come. In that sense, the grenade is the great equalizer.
But...what exactly is a grenade? How does it work? What are the different types of grenade?
And why has this humble explosive been a staple of world militaries for such a long time?
Answering these questions is exactly why we’re here today. First and foremost:
What exactly is a grenade? In its most general sense, a grenade is an explosive device either
thrown by hand or fired from another hand-held weapon, such as a Rocket Propelled Grenade - or
RPG - or a grenade launcher. Modern hand grenades have slightly more specific features
that we’ll get into later, including a delay element and a safety pin, but this perennial
family of explosives finds its origins in the arsenal of thousand-year-old armies.
You heard us right. Variations on the concept of the hand grenade have been
in use for well over a thousand years at this point. The earliest iteration of a hand-thrown
incendiary grenade has been dated back to the Ancient Byzantine Empire before the year 741
AD. These were essentially stone, ceramic, or clay pots containing a chemical compound
known as “Greek Fire”, believed to be a mix of the highly flammable naphtha
and the caustic quicklime. These terrifying weapons were shown to
be far more effective than swords and arrows, so naturally, they caught on across the East.
In the next 300 years, these rudimentary grenades found their way into both the Islamic world and
China. This is when it became combined with another Chinese invention to reach even greater
potency: Gunpowder. While the modern US may be synonymous with firepower and gun culture,
firearms were actually a Chinese invention, first devised at around 1000 AD. These primitive
guns were essentially lengths of bamboo filled with gunpowder that fired a spear,
known as the “Fire Lance.” That’s right - we had the granddaddy of grenades around 300 years
before even the most primitive form of gun. We wouldn’t have rifles until the 15th Century.
Over a hundred years prior, in the Chinese Song Dynasty, grenades got their first major upgrade.
The Chinese military introduced the Zhen Tian Lei, also known as the “Thunder Crash Bomb”,
which was a whole lot more like our modern idea of grenades already.
The shells around these gunpowder explosives were often made of cast iron, and they featured
a delay element in the form of a fuze - giving the user a little more time to make their shot.
India was also incorporating delay elements into their hand grenades during the 12th Century,
as records show terracotta explosives complete with fuses. Innovation was driving everyone in
the same direction, and inevitably, this shiny new piece of military hardware made its way over
to Europe. For the next few hundred years, there weren’t many changes to the fundamental design
of these thrown bombs: Gunpowder, cast iron or ceramic shells, and a fuse. Quite literally what
comes to mind when you picture a cartoon bomb. After all, why switch up a winning formula?
In the 1590s, we finally got the first use of the word “grenade” in English. It’s taken
from the French word for pomegranate, due to both the spherical design of the weapons,
and their tendency to explode into deadly pieces - much like the seeds within a
pomegranate. Grenades had become a modern combat mainstay. They were used in the English Civil War,
the Revolution of 1688, the Jacobite Uprising, and the Crimean War. The grenade was also
a popular weapon among pirates during the Golden Age of Piracy, between 1650 and 1730.
They also saw a reimagining during the American Civil War of 1861, with the introduction of the
experimental Ketchum Grenades among Union Soldiers. These grenades were shaped more
like large darts than the typical spheres - they featured a cast-iron payload full of gunpowder,
fitted with a pressure-sensitive plunger. The explosion would happen
when the plunger hit its target, and the tail end, fitted with aerodynamic fins,
was designed to help the Ketchum Grenade find its target. Of course, as we know from the fact
that modern grenades don’t look like this, these design principles didn’t catch on.
However, things weren’t always easy with the grenade. Early on, these weapons were often
dangerous and impractical, with heavy risks of going off at the wrong time
and blowing up its user. This became such a risk that, in the very early 20th Century,
the British War Office declared hand grenades as obsolete in modern warfare. However,
the success of improved grenades used by the Russians during the 1904 Russo-Japanese Wars
got them to change their tune. The British Government immediately began
work on modernizing the grenade for practical use in warfare.
This gave us some more precursors to the modern grenade, like the No. 1 Grenade developed by the
British Royal Laboratory and the double cylinder “Jam Tin Grenade” - an improvised grenade used by
the commonwealth forces during World War One. Grenade technology took a huge leap forward in
1915, with the introduction of the Mills Bomb in Britain and the F1 Grenade in France. These
grenades are a lot more superficially similar to the fragmentation grenades we know today.
They have the distinctive “pineapple” shape and grooved exterior everyone from
Navy Seals to veteran CoD players will know. But of course, progress isn’t always linear.
In Germany and Russia during World War One and Two, militaries flirted with the Stick Grenade - a
larger, heavier explosive cylinder on the end of a wooden stick, which allowed for longer throwing
distances at the risk of a higher weight. The most famous example is the German Stielhandgranate,
but the British also experimented with stick designs in the Second World War, such as the
anti-tank sticky bomb. Though none of these stick grenades survived for long after World War II.
The British also pioneered and mass-produced deadly white phosphorus incendiary grenades,
while the United States adopted the iconic Mk 2 hand grenade, which remained in active use all
the way up to 1969, before being replaced by the M26 and later the modern M67. These latter two
designs lost the pineapple appearance in favor of a more classic spherical look. This brings us
to today, and to modern grenade technology. We’re left with two questions: What are the
variety of grenades available to the world’s armed forces today, and how do modern grenades
actually work? What are the physical mechanics that makes these little metal balls go “boom?”
Before we dive into the how, let’s take a look at how many different types of grenades are
out there these days. First, we have the most common variety of grenades in modern warfare:
The Fragmentation or “Frag” Grenade. Generally made of steel or synthetic materials,
these grenades largely deal damage against enemy troops with both the blast itself and deadly
fragments of shrapnel - this shrapnel is the thick grenade casing blown to pieces by the blast.
They can be thrown around 130 feet, and have a harm radius of almost 50 feet.
When you picture a grenade in your mind, the frag grenade is likely what you’re thinking of.
Next, we have high explosive grenades, also known as concussion grenades. The key difference
between these grenades and frag grenades is that concussion grenades have a greater
weight and volume of explosive material within a comparatively thin outer casing. They generally
allow for a greater throwing range than a standard frag, but only have an effective casualty range of
around six and a half feet. However, actually killing is often not the objective with these
weapons. As the “concussion” name suggests, these grenades are mostly intended to stun the enemy.
Incendiary grenades, which we’ve mentioned a few times already, are the oldest variety of
grenades to exist, but they still endure in the form of thermite and white phosphorus grenades.
While these would obviously be devastating on human combatants with their maximum temperatures
of 2,200 °C/3,990 °F, their main purpose is destroying weapons caches, artillery,
and vehicles. For a more home-grown version of the incendiary grenade, see the infamous
Molotov Cocktail, a burning rag stuffed into a bottle of some kind of fuel, typically gasoline.
A key fact about grenades is that not all of them need to have lethal intent,
or even lethal capabilities. A number of grenades are intended for enemy disorientation in combat,
or even civilian crowd control. Take the stun grenade, or “Flash Bang” - a grenade that,
due to an immense chemical reaction within, produces a blinding, white light
and the sound of an explosion. It causes temporary blindness, disorientation, and a loss of balance.
The Sting Grenade, or Blast Ball, is a non-lethal fragmentation grenade designed for crowd control.
It’s a grenade that, upon exploding, fires out a large number of painful but non-lethal rubber
balls, often along with some eye-burning crowd control gas. Some riot control grenades purely
release tear gas, often to disperse crowds at public demonstrations. And finally,
smoke grenades, that - as you can probably guess - release large quantities of smoke
either for concealment or to mark a location in ground to ground and ground to air signalling.
Of course, it’s worth quickly addressing the outliers to all other grenade rules:
Impact Grenades. Rather than being hand thrown, these grenades are fired out of
weapons like RPGs and grenade launchers, and explode on impact with the target rather than
being timed. Obviously, these are a lot more precise than your standard hand-thrown frag
grenade, but they’re a hell of a lot more cumbersome to lug around the battlefield.
Now, what we’ve all been waiting for: How does a modern hand grenade, specifically a time-delay
fragmentation grenade, actually work? It comes down to the base components - the serrated metal
shell, the chemical fuze mechanism, and the actual reservoir of explosive material held within.
The chemical fuze is activated by the striker, which is in turn activated by the striker lever
on top of the grenade - this is what the iconic ring-pull safety pin keeps in place.
The soldier grips the striker lever and pulls out the pin before tossing the grenade.
This sets into motion the chemical reaction key to the grenade’s operation. Without the pin in place,
the spring-loaded striker lever automatically hits a component known as the percussion cap,
causing a small spark. This spark sets alight and begins burning the material of the chemical fuze,
a process designed to take around four seconds. When the fuze is burned,
the flame reaches the detonator, which is a reservoir filled with more combustible material.
This sets off an explosion within the grenade, blowing the outer casing apart into deadly
fragments that tear through anything unlucky enough to be nearby at the time.
And that is how a time-delay fragmentation grenade works.
This concludes our explosive crash course on grenades, one of the oldest weapons to
stand the test of time from the Byzantines to the battlefields of the Middle East in the modern day.
While the nuances of the design may alter over time, the longevity of the simple but
deadly grenade is a perfect example of how a good - and lethal - idea can always
endure - even in a world that feels as far removed from ancient battlefields as ours.
Now check out “How Powerful Is The Tsar Bomba?” and
“Atomic Bomb Vs Hydrogen Bomb - How Did They Compare?” for more explosive facts!