The Ultimate AR-15 FAQs
Few firearms have gained as much popularity in modern history as the AR-15. Originally designed by Eugene Stoner in the late 1950s for the ArmaLite company, this rifle uses a gas-operated action (direct impingement) that vents some of the fired gas back into the receiver to cycle the bolt. Over time, the AR-15’s design and versatility led to widespread use by civilians for sport shooting, home defense, and even competitive events. As the rifle evolved, many new manufacturers began producing their own versions, adding to its legendary status. In this guide, we present AR-15 FAQs to help answer the most common questions for first-time buyers. By covering everything from ammo choices to maintenance, you will learn what to know about AR-15s before making a purchase.
Table of Contents
AR-15 Ammo and Bullets
One of the most common AR-15 FAQs revolves around ammunition. The AR-15 was first chambered in .223 Remington, but many modern versions are also chambered in 5.56mm NATO. If your rifle is specifically labeled for 5.56, it can fire both .223 and 5.56 rounds. However, a .223-only chamber should not use 5.56 NATO because of slight differences in pressure and case dimensions. Another caliber that you might run into is the .223 Wylde. This is not “technically” a caliber it is a chamber specification. There’s a lot of technical information that I could go into but for new shooters the main thing to know is that it is generally more accurate, more expensive, and can shoot both 5.56 and .223 without any risk.
Magazine Capacity: Without a magazine, your AR-15 effectively holds just one round in the chamber. Standard magazines often hold 20 or 30 rounds, but capacities vary by state laws and personal choice. Detachable magazines can even hold up to 40 or 90 rounds in drum form.
Most Common Ammo: For most civilian shooters, .223 Remington or 5.56 NATO remains the top choice. Some people also use .223 Wylde chambers, which safely accommodate either round.
Best AR-15 Ammo: Many shooters recommend Federal XM193 (55-grain FMJ) or Federal XM855 (62-grain penetrator) for standard 1:9 or 1:8 twist barrels. Other brands like PMC and PRVI Partizan make similar loads. Prices can vary from around 30 cents per round in bulk to well over a dollar per round for specialty loads.
Other AR-15 Calibers
Another popular AR-15 FAQs topic focuses on caliber options. While .223/5.56 is the most widespread, some shooters use .22 LR uppers (the upper half of the rifle that can be quickly detached for cleaning) for inexpensive practice. Others pick specialty calibers like 6.5 Grendel for extended range or 300 BLK for heavier hitting power at shorter distances.
- Strongest AR-15 Caliber: Some argue that 6.5 Grendel offers the best long-range performance, while big-bore calibers like .50 Beowulf or .458 SOCOM provide serious knockdown force under 300 yards. With the ubiquity of the AR-15 and the slightly larger AR-10 rifles many other calibers have been developed. These go from .204 Ruger, 8.6 Blackout, and a whole host of wildcat (new and trying to become recognized) cartridges.
General AR-15 Questions
Below are a few more AR-15 FAQs many first-time buyers ask:
Background Checks: Federally, buying any firearm from a licensed dealer requires a background check. Some states allow private sales without background checks, so always check your local laws.
Waiting Period: There is no federal waiting period on AR-15s, though some states impose their own mandatory waits.
Break-In Period: AR-15 barrels typically do not require a strict break-in, but many shooters prefer firing 20-200 rounds to settle the barrel and confirm accuracy.
What Makes the AR-15 Unique: Its modular design sets it apart. You can swap upper receivers to change calibers, barrel lengths, and accessories for different uses like target shooting or home defense.
AR-15 vs. Shotgun: A shotgun has a smooth bore and fires shells that can contain shot or slugs. The AR-15 uses a rifled barrel and fires a single bullet per round.
Variety and Manufacturers: Hundreds of companies produce AR-15s, making it one of the most customizable rifles available. Prices can range from a few hundred dollars to several thousand.
AR-15 vs. Handguns (Danger): An AR-15 is not inherently more dangerous than any other firearm. Though it may attract media attention, the actual risk depends on usage and training.
Weight: A basic AR-15 with a 16-inch barrel weighs around 6.5 pounds without a magazine. Accessories like optics, longer barrels, or rails add weight.
AR-15 Barrels and Barrel Lengths
Barrel questions come up in almost every list of AR-15 FAQs:
Choosing a Barrel: The main factors are length and twist rate (e.g., 1:7, 1:8, 1:9). Lighter bullets work best with slower twists like 1:9, while heavier bullets (70 grains or more) often shoot better from a 1:7 barrel. The 1:8 twist offers a middle ground between these two. Longer barrels will allow for almost all of the powder in the brass case to burn in the barrel, improving velocity and range. There’s much more to talk about when it comes to accuracy, range, but this would turn an FAQ into a book.
Barrel Life: A well-maintained barrel that is well made can remain accurate for 20,000 rounds or more. Rapid firing and poor cleaning can shorten that lifespan.
Heat Concerns: Rapidly firing multiple shots in quick succession can make the barrel too hot to touch, affecting long-range accuracy. Be aware that sustained rapid fire can damage your rifle as you can see here. This is an extreme example however, using a fully automatic AR with an upper not designed for sustained full auto fire.
Legal Lengths: A rifle barrel must be at least 16 inches. Shorter barrels are allowed if they meet specific requirements, like being a registered AR-15 pistol with no stock attached. Consult your state and federal laws for more information about rifle, pistol, and short barrel rifle laws.
AR-15 Pistols
For those who want a compact firearm, the AR-15 pistol is another big topic under AR-15 FAQs:
Worth It? Many shooters find AR-15 pistols fun to use and easier to maneuver in tight spaces. However, shore barrel lengths severely impact accuracy, bullet velocity, and increase flash and sound.
Owning One: The lower must be registered as a pistol. You cannot attach a regular rifle stock, nor a vertical grip. Hand stops, and angled foregrips are generally ok. Braces intended to attach to the arm to increase stability can also be attached as of this writing, however the ATF is currently in court over their back-and-forth rules on pistol braces.
AR-15 Magazines
Magazines are critical to keeping your rifle fed and are a common point of interest in AR-15 FAQs:
Types of Magazines: Standard AR-15s use detachable box magazines in capacities ranging from 20 to 30 rounds or even higher with drum mags. When first introduced AR-15 magazines were metal, today polymer magazines are standard.
Reloading Speed: With training, switching an empty magazine for a loaded one can take just a few seconds, less with practice.
Storage: It is generally fine to keep magazines loaded, though some shooters rotate them every few months to preserve spring tension. With quality, modern, magazine springs this is no longer necessary, however.
AR-15 Maintenance
What to know about AR-15s also includes taking care of them:
Life Expectancy: Many AR-15 parts can last tens of thousands of rounds, especially if cleaned and lubricated correctly. The bolt carrier group (BCG) may wear out before the barrel does, so keep an eye on small parts.
Cleaning Frequency: Because the AR-15 has tighter tolerances, a quick clean after each range session is ideal. At a minimum, once a month or whenever the rifle feels grimy.
Preventing Rust: Most parts are either aluminum or polymer, but steel parts like the barrel and bolt need a light coat of oil and dry storage.
AR-15 Accessories and Customization
When it comes to upgrades, more AR-15 FAQs pop up:
Bipods: Mount them at the far end of the handguard. This offers better stability and leaves room for other accessories.
Slings: A two-point sling is most common. The best length depends on your body size and how you plan to carry or transition the rifle.
Suppressors: In places where they are legal, suppressors can reduce noise and recoil. They can make indoor shooting or hunting more comfortable. They require a NFA Tax Stamp and separate background check to buy. Additionally, suppressors change how the gas system of the rifle operates and if you do plan on adding a suppressor adjustable gas systems are recommended.
Cerakoting: Coating your AR-15 in custom colors can cost anywhere between $60 to $150 or more, depending on parts, colors, and design complexity.
Optics: Red dot sights are popular for short range shooting, LVPO’s (low power variable optics) give you much of the same as a red dot but with magnification and extra weight, scopes are also very common for distance shooting.
Others: Lights, lasers, Infared lasers, can launchers, and more. Just about anything you can think of can be strapped to an AR with picatinny rails. Whether or not you should is a different matter…
Best AR-15 for Home Defense
To wrap up our AR-15 FAQs, many first-time buyers want a rifle for home defense. For most a 16″ AR rifle is the best choice. An AR-15 pistol can be easier to handle in tight hallways but has major tradeoffs such as dramatically increased noise and flash. Indoors an AR-15 pistol is much like a flashbang and not as controllable.
Train with your chosen set up and seek expert advice in your equipment and ammo choices. Walk through your home and think about angles what lies behind each wall, a miss WILL punch through multiple interior walls.
Final Thoughts
These AR-15 FAQs should help you understand what to know about AR-15s before making your first purchase. Remember that local and state laws may affect your options such as magazine capacities, and even the types of accessories you can use. Most importantly, practice responsible firearm ownership. By choosing the right setup, maintaining your equipment, and staying informed, you can enjoy everything an AR-15 has to offer—whether it’s target shooting, hunting, or home defense.
