The AR-15 IS a military firearm and civilians should own them - change my mind

In all honesty, I don't like being divisive. However, I am very willing to be so if the cost is to be honest.  

I'll admit I'm of a certain political persuasion and because of that, I do enjoy watching Steven Crowder fairly often. Okay, okay, I know I'm sounding like a broken millennial record here, constantly spouting about freaking youtubers, but hear me out. Steven has made a pretty big splash on the interwebs and in national news for a variety of reasons, but I think his most enduring claim to fame is his "Change my mind" segments (I mean, it's still a popular meme). 

My only major disagreement I have with the good Mr. Crowder is his argument for defending the AR-15 and it's derivatives in his anti-gun control segments (including the Change My Mind specials). He states multiple times on his show that the AR-15 is not a military firearm and that they just look like military firearms. I doubt he is intentionally trying to be disingenuous in his stance, but it is a very dubious argument at best for defending the 2A, refuting gun control, or preserving the civilian right to own AR-15s, and it's blatantly inaccurate or dishonest at worst. 

Now, it's not a complete falsehood, there are some important differences between a military issue M4/M16 type weapon and what's commonly available to to civilians without extensive bureaucracy and licensing, but most of those will never make much of a difference at all in handling, performance, or looks of the gun. My argument being that they are basically the exact same firearm and design minus just one minor feature. They are so similar as to make almost no difference to the average person and they would likely never know the difference, even if they handled and shot both. This same reason is also exactly why the average citizen should never be restricted from owning it.  

One is civilian, one is military. Can you tell the difference? Does it even matter? Some will tell you the difference is just cosmetic, or that they are different guns and just look similar. This is all bullcrap.

For clarity's sake, the civilian AR market has such an insanely wide range of differing features and components to be ridiculous, but we'll operate on the principle that we are trying to compare to the average rifle that is advertised as an M4 style (or M-forgery) mil-spec AR which is still one of the most common to the average gun buyer.

So obviously, this whole post is to help those with little or no familiarity with specifically the AR design. For the uninitiated, here's a little primer on the parts of an AR-15 and another short video on how the AR-15 actually works. 

So, where's my proof for this, you ask? Let's make a small list of the similarities and differences in parts/components between the average civilian AR15 (in an Mforgery/M4 style) and a military M4 type rifle below: 

Similarities	Differences
Sights	Lower receiver
Pistol grips	FCG/selector
Handguards	Auto sear
Rail systems	Bolt carrier
Stocks	Barrel length
Upper receiver
Gas system/ Gas tube
Bolt head
Buffer and Return spring
Magazines
Muzzle Devices
Slings
Optics
Triggers
Selectors
Pins
Charging handle
Dust cover
Ammunition

Buckle up, this'll be a long one after the jump:

So, as you see the list of similarities are a lot longer than the differences between them. Every component on the similarities list above have either a 100% interchangeability/compatibility with the military rifle (unless a part of some custom or specialty rifle), or are so similar as to make zero difference. But compatibility isn't even restricted to the items on the similarity list, as I'll explain in a second. 

So what about the differences? Let's start at the top. The lower receiver. This component is still nearly identical to the ones on all civilian ARs and is still completely interchangeable with mating to any civilian AR upper receiver. The only actual difference in this larger component, is a small hole near the top edge of the receiver meant to hold the sear that helps makes the military gun either full auto or fire in bursts. See the photo below:

See that little thing in the circle? See it there? Also, photo shamelessly taken from Reddit.

Also, if you look at the picture above, below the circle around the pin in the lower receiver, you will also see the Fire selector.  The difference here is pretty small but important to mention nonetheless. As you see above the military version will have three markings, usually marked "safe, semi, and full" or "safe, semi, and burst". Most civilian ARs will either not include the "auto" or "burst" marking, since they don't have that ability, or not allow the selector to move to the third position, or allow you to move it and include the marking, but will not have any function, or some combination thereof. 

Which neatly brings us to the third difference, the auto sear. This is a small metal piece that is held in place by said pin mentioned earlier. This whole piece is obviously missing in most civilian ARs, as a full auto gun purchase requires a $200 tax stamp from the treasury department, a special FBI background check that is more extensive than a standard gun purchase, and registering both your personal and gun's info with the FBI and ATF. The actual sear component is highlighted in red in the picture below to illustrate:

Kind of obvious where I got that pic, no?

Now, as I mentioned earlier, you can technically still take a full auto lower to any civilian upper and it will work perfectly fine for the most part, full auto and all. However, on top of being a horrible felony with jail time and a fine, the bolt carrier would need to be strengthened for continued use on full auto to reduce wear and tear over time. Heck, even the military generally discourages use of full auto in most situations as it makes your follow up shots less accurate, and will either deplete ammunition much faster or outright waste it.  

Hence the fourth difference, the bolt carrier. now this is not as critical as other differences, and is once again completely interchangeable into a civilian AR. The only major difference is that the military bolt carrier has little extra weight and mass at the rear end of the carrier to help make the carrier a little more reliable and durable over time with full auto use. See the pic below:

Photo taken from here

Lastly, we get to the Barrel. This one is kinda funny in that a lot of civilian AR barrels are actually superior to the military M4 type barrel. The barrel on the military M4 is most often 14.5 inches in length, whereas the ATF and US law restrict the shortest length on a civilian rifle to be 16 (or 16.5) inches. Additionally, a good portion of civilian AR barrels are actually made to a higher standard than military quality, some with much more advanced production methods too. Since the AR shoots the exact same ammo as the military gun, the higher quality and additional length will generally make them a little more accurate and with a higher velocity to make them slightly more lethal than the military counterpart. This is kind of trivial though, since the average bolt action hunting gun is massively more lethal to humans than an M16, since they shoot far larger, more powerful cartridges. 

If you want to get into the minutia, you can also say they have different markings, but that makes zero difference to the gun for the user as far as function goes. 

On to the conclusion: Other than these small differences, they are exactly the same gun and have far more in common than differences. 

Why is this important? Well, the 2nd amendment is meant not for hunting, sports, or suppressing crime, but specifically for self defense against the government. To empower the average citizen to have the ability to resist tyranny by ensuring access to the same weapons (or same level of weapon tech) used by that government. 

That being said, once you understand the AR and how it works, it can come across as either ignorance at minimum, or intentional deception and dishonesty at worst to say it just LOOKS like an M16. They operate in the exact same manner, use mostly the exact same components, use the same ammo, and handle exactly the same with the exception of a full auto or burst feature. That is IT.