In part 1, we talked about the parts of a firearm cartridge.  Let's now take a (simplified) look at how these parts work together.  As it were, this little investigation will also show us why a cartridge going off without the benefit of a firearm isn't as dangerous as one might first think.

Most modern firearms have a hammer of some kind.  The hammer is the thing that makes the neat "cocking sound" when you pull back on it with your thumb.  When you pull the trigger, the hammer is propelled by a powerful spring and eventually hits a "firing pin".  The firing pin is little more than a small metal rod who's job in life it is to hit the primer on your cartridge.  In older firearms, the hammer used to come into direct contact with the cartridge, but this is no longer done.

Once the firing pin on your firearm hits the primer on your cartridge, the primer explodes.  This, in turn, sends a tiny column of fire into the portion of the case that is holding the powder. 

Gun powder comes in many varieties, each having a different set of properties.  One of the most important factors is the burn rate.  You see, gun powder is designed to burn gradually as opposed to creating a big "flash" ignition.  Why is this so?  Here is where we get into the nitty gritty of how bullets work.

As the powder burns, pressure inside the case is gradually increased.  In fact, the case actually expands until it fills out the space inside the firearm from which it is being shot.  Eventually, the bullet breaks free of the case, with the powder still burning and steadily increasing the pressure.  Since the case is securely held in place and is surrounded and enclosed by the firearm, the pressure building in the case has no other way to escape except down the barrel, ultimately pushing the bullet out at incredible speeds. 

All of this basically works because of a thing called Newton's Third Law Of Physics.  With that in mind, let's say you get unlucky enough to set off a cartridge on accident by dropping it on something just right, or inadvertently striking it with something - what happens?

First, the primer explodes.  No two ways about it.  This, inevitably, will ignite the powder.  Now, the pressure inside the case begins to build.  Next, one of several things will happen (depending on a combination of the weight of the bullet, the structural integrity of the case and the type and quantity of powder used in the cartridge). 

The first thing that might happen is that the case ruptures (tears) and the gases created by the burning powder escape more or less uninterestingly. The bullet may or may not be flung about, but most likely not with lethal force.  Remember - the reason bullets fly to darn fast is that the pressure from the burning powder is channeled very directly behind the bullet traveling down the barrel.

The second likely thing to happen is that the pressure increases until the bullet is freed from the case.  Again - due to lack of a barrel channeling the pressure, the pressure will just escape the cartridge more or less uninterestingly.  Make no mistake about it, there will be a loud crack and you will likely feel a tiny shock wave from the explosion, but it will not be focused. 

In both of these scenarios, the energy from the burning powder is more likely to fling the case, rather than the bullet, around.  This happens because the case is lighter than the bullet and is easier to move.  Since the case isn't being held in place by the firearm, the force of the explosion is free to move it about.  Of course, a brass case flying around at incredible speeds can can still be dangerous, but nowhere near as dangerous as a bullet coming out of the business end of a gun.

Remember seeing those movies where they drop a bunch of ammo in a fire only to have bullets whizzing around in every which direction?  While entirely unsafe and dangerous (i.e. don't be an asshat and try it at home), that scenario is probably more fiction than fact, even if it would be extremely disturbing and scary.

So there you have it.  Try not to drop your bullets (cartridges) on the ground.  If you do, however, just remember that even in the unlikely event that you do set off the primer, you'll probably be okay.  Stay calm and don't pee on yourself - 'cause that's not a good look!

Remember to wear safety glasses and clothes that cover you up when you go shooting.  Even if nothing ever goes wrong, ejected cases are damned hot and WILL give you nasty burns that WILL leave a scar (especially if they happen to fall down the shirt of your female companion where the case isn't immediately retrievable - don't ask).

When dealing with firearms, one inevitably needs to deal with bullets.  Technically, guns aren't dangerous - bullets are.  That being said, as long as you treat ammunition with the same respect that you treat, say, electricity - you'll be fine.

So let's say you're at the range handling a fist full of large .45 caliber ammo and one tumbles out of your hand (in slow motion, 'cause everything is scarier in slow motion) and heads straight for the gravel floor beneath your feet.  A particularly pointy and mean looking pebble briefly glistens in the light of the afternoon sun and you just KNOW that round is going to hit that evil pebble square on the primer...setting off an inevitable chain reaction that will result in your or someone else's head being blown off by a stray bullet that you careless failed to hold on to. Every muscle in your body instinctively tightens in anticipation of the inevitable...

*CLINK*

Nothing. 

Phew!  It didn't happen - that time.  That was dangerous... or was it?

Actually, it is possible to set off a round with something other than the firing pin in your firearm - like a pointy rock or a hammer, or heat.  And while you shouldn't be setting off ammo without the benefit of a firearm, it's not as dangerous as you might expect.

In Part 2 of this post, we'll take a simplified look at the internal ballistics of how ammunition works.  First, however, let's take a look at the parts of a modern cartridge (picture borrowed from HowStuffWorks.Com).

The whole thing is called the "cartridge".  It's called that because it contains several parts.  As a matter of convenience, you can order a box of "bullets" at your local gun counter and everyone will know what you're talking about, even if it's not technically accurate.  Nobody buys a box of "cartridges".

The outer hull of the cartridge that contains all the other parts is called the "case".  This is the part of the cartridge that gets spit out of the side of your firearm after you pull the trigger. 

The very top portion of the cartridge is the "bullet".  That's the part that comes flying out of the front of your firearm after you pull the trigger.  The bullet is literally stuffed into the case and crimped into place during manufacture.  There's nothing else holding the bullet in place except the case hugging it snugly there.  It is, in fact, possible (and even common) to disassemble a cartridge by manually pulling the bullet out of the top.  In an emergency, this could be done with a pair of pliers but this is dangerous and can cause serious harm to you or others nearby.  Under normal circumstances you want to use an actual bullet puller.

Just beneath the bullet, is an empty space filled partially with the propellant.  The propellant is normally some kind of gun "powder".  It's the powder's job to create the pressure required to propel the bullet out of your firearm.

The powder is worthless unless you can ignite it somehow.  That's the job of the final component of our cartridge: the "primer".  Incidentally, the primer is the most unstable part of the bullet (much more unstable than the powder, actually).  The primer's job is to explode when it receives a sufficiently forceful whack.  Under normal circumstance, it's the firing pin in your firearm that does this.  If something else hits it hard enough, however, it will ignite just as readily. 

In part 2, I'll take a look at how all of the components of our cartridge work together to do its business.

I'm not a particularly political person.  Sometimes, however, I see statistics that make me question humanity in general.  I think this speaks for itself:

• Europe & The United Stated spend about $17 billion annually on pet food.
  • It would take about $19 billion annually to eliminate world hunger.
• We spend about $15 billion a year on perfume.
  • It would take about $5 billion annually to achieve universal literacy.
• We spend about $14 billion annually on ocean cruises.
  • It would take about $10 billion to give clean drinking water to all humans on the planet
• Europeans spend about $11 billion annually on ice cream.
  • It would take about $1.3 billion to immunize every child in the world against dread diseases

The United States has roundabouts 32% of the world's wealth, but contains only about 5% or 6% of the world's population...

The top 1% wealthiest people in this country control more of this wealth than the bottom 90%. 

Bill Gates alone controls as much as the bottom 40% of U.S. households.

Well done.