How An AR-15 Works By: William Lawson


Do you ever wonder how your AR-15 rifle works? I know we all understand what happens when we insert a magazine, charge the action, and pull the trigger, but do you know exactly what goes on inside the rifle itself?

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AR-15 magazine catch
How the magazine catch works.

Maybe you do, but not being especially mechanically minded, I didn’t. So, if you’re like me, you’ll appreciate the video below that lays it all out. YouTuber Matt Rittman has created an animated representation of the AR-15’s functions. All of them. It’s well put together and narrated to explain exactly what you’re seeing. It highlights the rifle’s parts as it discusses them and sometimes provides replays from different angles. I think even expert gunsmiths will enjoy this video.

AR-15 bolt carrier group
Bolt carrier group operation.

Exposing the AR-15’s Guts

From the time you insert the magazine, the AR-15 has something going on inside. Charging the action, flipping off the safety, and squeezing the trigger all make things happen that we don’t see. Obviously. For instance, I know the bolt carrier group’s cam pin turns the bolt and locks the lugs. But I’ve never seen it happen.

Cam pin and cam pin track
Demonstrating the bolt carrier group’s cam pin operation.

Likewise with parts like the extractor. I know, conceptually, how it works, but it’s not something you can really watch. Until now. The video also covers the trigger mechanism, from the trigger itself to the sear, the hammer, and on to the firing pin.

The AR-15 bolt loading a round
The bolt strips a round from the magazine, loading it into the chamber.

It even animates the 5.56 NATO cartridge, complete with primer ignition and the rifle firing. Which goes on to the gas and recoil system. You get it.

AR-15 hammer
The AR-15’s hammer.

One of the video’s more interesting parts shows how the M-16 and M-4 operate in select fire and burst mode, as opposed to the AR-15’s semi-automatic mode. Again, I’m not mechanically inclined, so I appreciated that bit since I could see the differences myself and how they work, even if I don’t fully grasp the nuances.

5.56 NATO cartridge cross section
The 5.56 NATO cartridge.

This very thorough video covers front and rear sight adjustment, magazine insertion and ejection, stock adjustment, and how the buffer works. It even shows how to operate the forward assist, something most people will never use. I don’t know whether Matt Rittman is a gun guy, but he gets the terminology right too, which I appreciate very much. I expect that media types throwing out stuff they know nothing about annoys you as much as it does me.

AR-15 gas system
Illustrating the AR-15’s gas system.

An AR-15 Educational Tool

I’ve already bookmarked this video so I can return to it as needed. Not only will it help me with my blasters, but I also think it could be very useful to help new shooters and gun owners familiarize themselves with their rifles.

Extraction and ejection
Extraction and ejection system.

With most machines, I couldn’t give a rat’s rear end what makes them go. I’m just not interested. But my guns are different. I spend a lot more time taking them apart and reassembling them than any other machine, including my car. I’m firmly convinced that’s why God created auto mechanics. Gunsmiths too, but those are fewer and further between. Even I know I should understand how my guns work and how to perform basic maintenance and repairs. For the record, I can also do basic stuff with my car, but it’s mostly against my will.

AR-15 auto sear
The auto sear as part of select fire.

This video helps me see how my ARs are supposed to work. It also shows me all the moving parts, which, in my mind, helps me maintain them so they keep moving like they’re supposed to. Maybe you think I’m full of it, and that’s fine. I reached the same conclusion a long time ago. But whether you’re a certified AR-15 armorer or just a rube like me, I bet you’ll find this video interesting and maybe even helpful.

M-4 burst cam and clutch spring
The M-4’s burst cam and clutch spring enable burst fire.

Rittman also has similar videos for the AK-47, Remington Model 870 shotgun, Mauser K98 rifle, and the Glock pistol. Very cool stuff. Happy shooting, y’all.