3D Animation Shows How an AR-15 Semi-Automatic Rifle Works
Do you love the sound and power that comes from a gunshot as much as I do? Now pair that exhilaration with hitting your target.
Time at the gun range helps you focus and release tension.
But what about those times when your shot isn’t accurate? Was it human error or mechanical? I don’t think we realize what it takes to get our bullets to their targets.
A simple shot of a round from an AR-15 rifle requires a series of perfectly timed events that take place within a fraction of a second. The mostly smooth exterior of the gun hides the magic that’s happening inside. The moment your finger pushes the trigger into the right place, parts start moving.
No, your finger movement doesn’t automatically cause a powerful hit to the back of the bullet that sends it down the barrel.
For an efficient shot, you need a trigger, a hammer, a pin, and primer. The trigger you pull releases the hammer. It strikes a firing pin which in turn strikes the primer. You already have four activities and you haven’t even come near the bullet yet.
What pushes the bullet out of the chamber is actually gas. The primer’s explosion ignites powder with a high burning rate. This fast burning produces gas inside the gun which increases the pressure instantly. The only thing that can compensate for this change is the bullet and so it’s pushed outside via the barrel. The gas pressure is what gives your bullet so much speed.
But an AR-15 semi-automatic rifle isn’t loved only for its accuracy. I love it for how quick you can take your next shot. Who wants to waste time reloading, right?
The gun’s intricate design uses the gas optimally. Instead of letting it escape with the round it’s diverted back into the gun.
In order to ensure that the gun fires smoothly, a small portion of the hot gas which propels the round are diverted from the barrel and brought directly to the Bolt Carrier Group (BCG). This automatically chambers a new round.
The parts quickly move as the gas pushes the Carrier backward. Now there’s space for the gas to escape through vents and there’s space for the empty casing to retract. It reverses back into the gun’s mechanism and is then expelled.
I love seeing those casings being flung far and wide across the shooting range. No wonder safety gear is mandatory. But the flying parts showcase the power of the AR-15.
And what takes the casing’s place? Another bullet from the magazine.
This is why it’s so difficult to push down the last few bullets you load. The spring inside the magazine must provide enough power to push new bullets into place the moment empty casings exit the gun.
Of course, the AR-15 rifle is as safe as it is powerful. A simple safety catch is all you need to prevent your trigger from starting the succession of movements that enable your shot.
Watch this 3D animation of how the basic AR-15 semi-automatic rifle operates as it fires.
Elena D'Onghia, an associate professor at UW–Madison, has proposed a new concept for a Halbach Torus (HaT) to help protect astronauts from cosmic radiation.