The AR-15 has been around for longer than most of us. It is a controversial gun, but it continues to be effective for a very diverse set of tasks, so most of us in the 2A community love it. But it can be intimidating for those new to shooting sports.

We’re going to break down those barriers. Here at AT3, we see a lot of questions about the gun. Here are answers to the 10 most common questions about the AR-15.

#1. What is an AR-15?

In the most traditional sense, the AR-15 was a rifle built by Eugene Stoner as a replacement for the heavier military rifles of the day. This was the late 1950s, and the AK-47 was the best rifle design on the planet, but the US was still running with Garands and M-14s–heavy .30 caliber guns that were designed for wars of the past.

Magpul L Plate 3 pack for AR-15 Magazines .223 / 5.56 NATO - MAG024-BLK
The AR-15 is easy to recognize. It has become iconic.

Stoner first built a .308 version, but then adapted the design for the 5.56 cartridge. The resulting gun entered military service as the select-fire M-16, but the semi-auto version was the AR-15. These guns were lighter, and fired a lighter round, which meant the gun was easy to carry.

Today AR-15 is a general term used to refer to a family of guns. Think of it as a theme, of sorts. One of the defining aspects of the AR-15 was its modularity (lowers, uppers, furniture, barrels–all available to be mixed and matched). This mix-and-match design means there are countless variations on the theme.

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AR-15s are now chambered for rounds other than the 5.56 and .223. Some, like the .308 versions, even get their own nomenclature–AR-10. But they’re still ARs.

And that naming may be further complicated by all of the nicknames. AR, AR-15, modern sporting rifles (which is a bit broader), black rifles… there are many euphemisms. If the gun looks something like an AR-15, it is likely to get grouped in with the original–even if it is functionally similar, at all.

Eugene Stoner.
Eugene Stoner.

#2. What does AR mean in AR-15?

The media may want you to think AR means Assault Rifle. It doesn’t. Stoner, the man with the plan, was working for Armalite when he built his first prototypes. Even though the early M-16s were built on contract by Colt, this is an Armalite design.

AR means Armalite Rifle.

#3. Where to buy an AR-15?

Not all states in our great union agree on this. Some states won’t allow FFLs to sell certain guns, and the AR-15 is one of the most commonly banned. If you live in those states, this is a complicated question.

If you live in one of the gun-friendly, the options are endless. At least they should be. Sometimes an increase in demand keeps available stock low, but let’s assume they’re in stock.

Most gun stores carry them. There are numerous home FFLs who sell guns without typical retail spaces. They can help, too. And there are lots of big-box stores that carry them.

Online, there are resources that will allow you auction-style and buy-it-now options. They all require you to transfer the guns through an actual FFL. Then there are gun shows.

The lower is the only serialized part of the gun and has to be transferred through an FFL.
The lower is the only serialized part of the gun and has to be transferred through an FFL.

For those who want to build their own AR-15, there are some solid parts suppliers. We can help with that, for sure. There’s only one part of the gun that is serialized–the lower–and that has to be transferred by an FFL, just like a complete rifle.

For those who want to make their own, there are companies that will sell partially finished lowers. Because it is legal to build your own, you won’t need to involve an FFL. But you’ll still need to find parts, and finishing a lower requires a bit of skill with hand tools or milling machines.

You don't have to have gunsmithing tools to build an AR, but they can make the job much easier.
You don’t have to have gunsmithing tools to build an AR, but they can make the job much easier.

#4. How to build an AR

Building an AR is surprisingly easy. All properly modular pieces fit well. There are some small pins and springs that require a bit of manual dexterity to manipulate, but they’re not bad.

The build process deserves its own breakout, and we have that here. If you get even halfway serious about the process, pick up some good tools.

But think of it this way–when you build your own AR, you control everything. And you can do it in stages to keep the cost manageable. It is crazy addictive.

Most AR-15 builds happen in sections or parts groups. Build an upper, with a bolt carrier group, barrel, and forend. Then build a lower receiver group, with all the parts of the trigger group and a grip and stock. This can help spread the cost out over time.

#5. How to build 9mm AR

Much like the section above, building a 9mm AR isn’t complicated. All you need is an appropriate set of parts built for the caliber.

Faxon Firearms 9mm 4.5 inch AR15 Barrel – Light Tapered - 4150 QPQ
Some 9mm barrels, like this Faxon, are short!

The 9mm barrel is unique, as is the bolt carrier. The lower needs to run 9mm mags. The rest of the parts are typically the same, so there’s no real learning curve for anyone who has built a 5.56 AR-15.

In other words, decide on the basic design that you want to build and shop for the parts that are common to all ARs, like the stock, grip, and forend–and then source the specific 9mm parts that are compatible. The end result will be a versatile PCC.

#6. How much does an AR-15 cost?

How much money do you have? Just like everything else in this world, someone will sell you an AR-15 that costs more than most American houses. But that’s not why we’re here.

The typical price range runs anywhere from $250 when supplies are plentiful up to well over $3,000 for some boutique brands.

There are a couple of points in the middle that serve as benchmarks. The under $500 guns are increasingly rare. Demand has driven up price and these, when they are available, don’t sit on shelves long.


The under $1,000 guns are typically available and have the solid trust factor that comes from brand names. These are usually well-built, made from quality components, and are popular with shooters who want a functional gun they can then modify.

The next break tends to hover over or under the $1,500 mark. While some brands will push MSRPs up to $2,000, the market usually brings retail prices back down a bit.

How much an AR will cost is determined by its features, true, but mostly by the demand. In times of political turmoil, prices skyrocket.

These aren't for your teeth. Otis makes great brushes.
These aren’t for your teeth. Otis makes great brushes.

#7. How to clean an AR-15

If you have cleaned guns, this one will be easy. Be safe. Check the chamber and check it again and make sure your mags are empty.

The one part that can be tricky is the bolt carrier. The AR, like some other guns, is designed to be broken down into two parts (the upper and lower). Remove the upper from the lower, and you can then pull the bolt carrier from the upper.

This is an essential part of field stripping. You don’t need to take everything down. Just address the moving parts. Add some oil, wipe down surfaces, swab the bore if a visual inspection of the unloaded barrel shows debris or dirt.

The bolt carrier, though, gets nasty. You’ll need to scrape it down good–away from the range. A specialized tool can make the job much easier.

For an advanced clean, you may want to take apart the BCG or the trigger. There’s no need to do that every time you come home from the range. Maybe once a year, or once every 5,000 rounds–its up to you.

Need a more detailed explanation of cleaning your AR?  Check out our article here.

#8. How to check AR-15 headspace without gauges

If you do get into building or deep cleaning guns, you’ll need to check on some important measurements. One is headspace. There are many gauges for checking this, but few AR owners have them.

So how do you check AR-15 headspace without gauges?

Safely remove the BCG. Pull the actual bolt head from the BCG and remove the extractor and ejector. Now put it all back together.

Insert a clean brass case into the chamber and reinsert the BCG into the upper and close the action. If it closes tight, you know you have enough (and maybe too much) headspace.

If the BCG won’t slide into battery on that case–which you’ll see because it sticks out the back of the upper (maybe as much as 1/8th of an inch), you don’t have enough headspace.

In some instances, a case will rattle just a bit in that closed chamber if there’s too much headspace. But it may not.

The real indicator will be the state of the brass after you fire a round. If you have more headspace than you need, the accuracy of the gun may suffer, but the brass may have odd areas of expansion that would prevent it from being reloaded.

It doesn’t hurt to have a set of go/no-go gauges. They make everything easier.

This is a brief overview of checking headspace.  If you need more information, see our article on the topic.

This AT3 RD 50 has a 3X magnification. That's built in. For more, add a 3X magnifier.
This AT3 RD 50 has no magnification. If you need some, consider adding a 3X magnifier behind the red dot.

#9. Where to mount a red dot on AR-15

This one is much easier to tackle. Most AR-15 uppers have rails on the tops of their uppers. This is the ideal place.

If you want a scope for distance and a red dot for speed–both on the same gun–you’ll need to mount the red dot on the scope mount. That may take a specialized mount.

If you want a red dot and a magnifier, mount the red dot farther forward, then mount the magnifier behind it.  We have an entire article on this topic – read it here.

Learn more about AR red dots here. 

MFT makes some minimalist stocks that can cut weight.
MFT makes some minimalist stocks that can cut weight.

#10. How much does an AR-15 weigh?

This one, too, is easy. If you go super light, a pistol or carbine build can come in at 5 pounds. This relies on some high-tech components, like carbon fiber and titanium. Understand that the lighter the gun, the heavier the investment.

But the lightest guns are not without their faults. Weight mitigates recoil. Weight provides stability. This shouldn’t be a deal-breaker, though, as the 5.56 or .223 are really easy on the recoil.

Look at the long .30 caliber designs on the other side. They’re typically well above the 10 pound mark, and sometimes up near 14 pounds once you fit them with optics and bipods and all of the accouterments.

These are just the 10 most common. There are other questions, too, we know. Leave them in the comments below and we’ll get started on round two.

One Last Tip

If there’s anyone that knows the AR-15 platform, it’s the US military. As a special offer for our readers, you can get the Official US Army Manual for AR-15/M4/M16 right now – for free. Click here to snag a copy.

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2 thoughts on “Top 10 Questions about AR-15s Answered

  1. Very good article especially for someone just getting into the a.r. Lego game. It can get very overwhelming with all the parts and products.

  2. AR does not stand for Armalite Rifle, it just stands for Armalite. AR-9 and AR-17 were shotguns and AR-13 was a multi-barrel aircraft machinegun.

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