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Parts of a Bullet

What are the basic components of Ammunition


Right no messing about, let’s get straight into it.


What are the 4 components of a bullet


They are, as follows:




This is usually made from brass, cooper, or steel and it holds all the other parts of the ammunition together. Shotgun shells are a bit different; their casing is plastic with just a little bit of brass covering the base of the cartridge.  

The casing in most guns gets expelled out of the side of the firearm.

This casing can get you into trouble if you are the villain of a TV Crime Drama, as the way the casing comes out of the gun and the marks that are left on it are unique to the gun used.

You know the scene, the Detective finds a casing under a couch, and it blows the case wide open!




The primer is either found on the rim of the case or in the centre of the base (usually the center nowadays), depending on if the ammunition is a rimfire or centrefire respectively.

The aim of the primer is to ignite the gunpowder after it has been hit by the firing pin, to achieve this the primer must be an explosive chemical.

All of the parts of a bullet work together so that it functions correctly, but arguably the primer is the most important.

It has to sit there safely and dormant, until it is hit in exactly the right place with the required force, then it becomes an angry, volatile, and powerful force.




We will all have heard of gunpowder I presume, basically it is a chemical that is easy to burn and when it does burn it turns into a powerful expanding gas. Gunpowder is usually made from charcoal, saltpepper, and sulfer.

The gunpowder explodes when the primer is activated, the explosion producers a huge amount of energy that is contained by the casing, so it expands and pushes the projectile forward with great power and intensity.

The path of least resistance.




The expanding gas hurls the projectile through the barrel and at the target.

It was generally made from lead as lead is easy to manipulate and shape, most projectiles are cylindrical and are aerodynamically shaped for maximum speed and accuracy. But there are many materials used in the modern era like cooper.

The explosion from the gunpowder is so powerful that the majority of bullets travel faster than the speed of sound. Which is pretty awesome when you think about it.

Technically the bullet is only the projectile part of the whole show, but in modern day language it is often the term used for the whole sherbang.

That’s it really, article is finished! Oh ok, I’ll go into a little bit for detail for you because yes, the parts of a bullet are simply the casing, primer, gunpowder, and projectile but there are a few more things we can delve into, to flush out the story and give it a bit more context.


Evolution of the bullet


If you have ever seen the movie The Last of the Mohicans, which is a great film by the way. But how quickly they were able to load and shoot their rifles was ludicrous.

In those days, there were no self-contained bullets. Everything had to be loaded into the rifle manually which was slow and laborious.

You had to load the projectile from the front of the barrel, then you had to have a separate bag for the gunpowder which you would pour into a percussion cap or a flash pan, with something used as a fuse instead of a modern-day primer.

If you have seen old actual videos or realistic films with replicated guns from this era, it was almost comical.

People putting a little round bullet in the barrel, putting some sort of wadding in after it, and ramming it down repeatedly with basically a posh stick, with an action that might be deemed rude nowadays.

So, you had best be a good shot, because in those days you likely didn’t have time for a 2 shot!

When you think of all that, it is amazing how far we have come since then, especially when you consider things like automatic machine guns never mind things like missiles.


Bullet weight


If you are just a beginner, or if you just have a gun for home self-defence then bullet weight isn’t a big deal… just use bullets that fit your gun and get yourself down the range for some practice.

But if you are interested in improving your accuracy and tailoring your bullet to its intended target, then weight does become a factor you should consider.

Bullet weight is usually measured by grains. Not a scale with a box of Kellogg’s on it as a counterweight, but a very small unit of measure. Where 1 pound = 7000 grains.

For example, if you see a bullet listed as 9mm 115gr FMJ, that is a 9mm Full Metal Jacket round that weight 115 grains.

You can buy bullets as light as 15 grains, and as heavy as 600 grains. So, there is a pretty decent range of weights you can buy depending on the guns you own obviously.

A lighter bullet in perfect conditions like in an indoor shooting range, with likely travel further and more accurately than a heavier one.

However, in more extreme conditions a heavy bullet will be less effected by things like wind and rain and they cause more damage on impact.

So, which is best depends on the when, where, and why.


Bullet shape


The shape as well as the weight is important. For the most part the aim of a bullet is accuracy, so that it hits the intended target.

So, they must be aerodynamic, so that they can travel and far and as fast as possible without deviation. Generally, you may also want to cause as much damage as possible, for example if you are in the military or hunting game.

However, these two aspects are at odds with each other. The most aerodynamic bullet will be thin and be pointy at the end.

However, to cause maximum damage they are better off being rounded, with a hollow point which expands on impact.

So, if you need one of these two extremes then you should buy bullets to suit your intended purpose. But you will find a lot of shapes in between, if you are just a general shooter.


Bullet material


Again, materials will impact how the bullet flies through the air, the accuracy, and the damage it causes. The projective is often made from some combination of soft lead, cooper, and harder steel.

Therefore the materials will need to suit what you intend the bullet too do, if you are just messing around at the shooting range on a Sunday afternoon then it doesn’t matter much.

If you want to kill a small animal and not spoil the meat then you will need a hard projectile that doesn’t expand, and if you have a terrorist running at you, then you might want a soft bullet that expands and therefore causes more damage.

Basically, to get a perfect bullet for a specific need, then you will have to experiment with combinations of weight, shape, and materials together.


A brief timeline of the bullet through history


The evolution of the bullet is always moving forward, below I’ll cherry pick a few important leaps in technology that keeps breaking new bullet boundaries:




The Chinese were messing around with fireworks way back in the 10th Century. It didn’t take too long to realise that this invention of gunpowder could be weaponised. 

In fact, one of the earliest versions on a gun was more like a rocket launcher and came from the Arab empires. Basically, they were reinforced hollow bamboo canes, where the gunpowder was used to fire out arrows.


Lead balls


There was a lot of experimentation with firearms and bullets over the coming centuries. Wood projectiles that made little damage, to iron balls that caused a lot of damage but were labour and material intensive… therefore costly.

Lead balls brought bullets to the masses. They were cheap to make, and importantly they were easy to make as lead to easily melted over a small wood fire.




Balls became a thing of the past, as a more modern the cylinder look emerged, which coincided with making the inside of the barrels grooved. This spun the bullet as it left the barrel, meaning to flew longer and more accurately.

The flat end of the base of the bullet allowed for a snugger fit in the barrel, meaning the explosion was more contained and therefore more powerful, yet the rounding at the front of the bullet still made them aerodynamic.


A safe primer


The problem with all early guns was a trade off of how quickly you could ignite the gunpowder without blowing your face off!

In the 1800’s mercury fulminate and potassium chlorate was mixed to make the first widely used primer, that was safe but very easy to ignite in a controlled manner with early versions of the firing pin.


Gunpowder’s evolution


Gunpowder is probably one of the things that has shaped the human species more than anything in the modern era, as it took warfare to a whole new level. But the formula had hardly changed since the 10 century.

It was effective but it was messy and produced a lot of unpleasant smoke. You could often see a bullet coming towards you because of the plume of smoke.

So, a new form of gunpowder was developed called cordite. Which is smokeless and was in a much easier pellet form.


Rim-fire bullets


In the 1850s the first bullet emerged that was practical for warfare and widespread use. This was when we saw the introduction of a self-contained bullet with the casing, primer, powder, and projectile in one unit.

The firing pin would hit the rim on the cartridge, damage it, and that would ignite the primer.


Centre-rim bullets


Rim-fire bullet had to be thin and made of soft metal, so that the firing pin could damage the bullet to set off the explosive charges. This limited the range, effectiveness, and damage the bullet could cause.

But weapon technological advancements were moving fast now, and the centre-rim bullet came to the fore and is still the most widely used today.

The primer is housed in its own container which it the only part that still needs to be damaged by the firing pin.

The rest of the casing can be made from different materials meaning you can have a stronger casing, meaning you can use more gunpowder, meaning you have faster and more powerful bullets.


Frangible bullets


Frangible bullets seem to be where we are heading now, think of them as “safety” bullets. They are designed to expand more when it hits a person or animal causing more damage than a traditional bullet.

But if it hits a wall or a tree it simply breaks apart. So, you cause more damage to intended targets, but you have very little impact on anything else.


Final thoughts


Hopefully, this article has been of interest to you and you have a better idea of how a bullet is made, its historical impact, and how best to choose the right bullet for the right occasion.

The traditional bullet we know and love today has been around for quite a while, which is surprising considering how much the world has changed since its invention.

Maybe the move away from gun warfare to long range missiles and drones have slowed the bullets development, but I wonder how long it will be before we find ourselves using some sort of gun you would find in Star Trek or Star Wars.

Do not laugh because if you told someone from the 1700s that you had a self-contained bullet that you could hit someone with, over 2km’s away with a sniper rifle… they would laugh in your face!

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Hi - I'm Tom, the owner and founder of TheSurvivalSpirit.com! I'm a passionate outdoors enthusiast and am dedicated to bringing you the hottest online survival advice.  


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