The Best AR-15s: Everything You Need to Know

The AR-15 platform gets a lot of attention, and for good reason, it is one of the most reliable and versatile firearms ever created. A modern sporting rifle is my go-to for almost any shooting activity home defense, distance shooting — you name it.

Both long and short-barreled rifles are all possible with a single AR-15, which is why it’s one of the most popular semi-automatic rifles available today.

Invented by a renowned team of engineers who were looking to change the dynamic of what constituted small arms at the time, the gun has gone on to be known and respected around the world. This article is part of our Guide to Everything AR.

There’s an ideal AR out there for everyone, and below is my list of the best AR-15 rifles, which takes into account quality, reliability, ergonomics, and our real-world experience.

1. Editor’s Pick: Palmetto State Armory PA-15

What we liked:

• Solid availability
• Serious bang for the buck
• Lots of PSA products to choose from
• 1:7 barrel twist rate is good middle ground

What we didn’t:

• There are higher-quality builds available
• Not a drastic improvement over previous-gen PSA ARs
• Controls can run a touch loose

A quality (and customizable) workhorse AR

Long an AR component producer, Palmetto State has made an impact as an AR-15 manufacturer. Palmetto State’s PA-15 mil-spec AR-15 uses standard components but I love how they pair a 4150 Chromoly 16-inch, cold hammer-forged barrel with a classic A2 pistol grip, carbine-length gas system, and melonite finish for some throw-back goodness.

Beyond the components, PSA owns the production behind these ARs, so I can generally always find a few in stock in various configurations, which can be a rarity given the kind of surge in demand for ARs (and firearms in general) in times of crisis.

Flaws worth noting

My main issue with the PSA is its carbine-length gas system paired with the 16-inch barrel which tends to over-gas the gun. I wouldn’t say it’s a major flaw, but an adjustable gas block will help dial the rifle to your liking if you find it too snappy.

Sure, you’ll be able to power through the cheapest ammo available (and given recent trends *cheap* is probably the wrong word), but I found it produced a forward (2 or 3 o’clock) ejection pattern out of the box.

Not a killer, but something that we’d like to tune out to get it humming like a Singer.

I’ve also had a PSA BCG freeze up on me without proper maintenance. Not unique to the PSA rifle, but one of the few instances when that has happened to me.

A fun, functional middle ground

The 1:7 twist rate barrel gets 62 & 77-grain ammo to the target in a tight group – but also performs well with 55-grain. Paired with a halfway decent LPVO, I can ring 8-inch steel from a standing position at 75 and 100 yards all day long.

As with all classic A2 birdcages, there are no ports on the bottom so you’ll avoid kicking up dust when firing prone.

All-in-all PSA has produced an outstanding rifle and continues to use its massive component infrastructure to deliver fun, high-quality products. Sure, there are higher quality, better-designed ARs out there, but for a first AR or a 5th, I think the PSA hits the sweet spot of value and performance. For more check out our PA-15 long-termer review.

2. Premium Pick: Daniel Defense DDM4V7 Mil Spec AR-15

What we liked:

• Incredible build quality
• Gold standard for reliability
• Mid-length gas system makes for softer shooting
• California compliant options

What we didn’t:

• Trigger feels heavier than it should
• Vertical grip is mounted in an awkward location from factory and limits hand position options

A top-tier AR if there ever was one

The company that made AR rail systems famous has produced some of the most popular rifles now for a generation. A long-time favorite of mine, the Daniel Defense DDM4, especially the V7 series gun, uses a cold hammer forged government profile barrel that does away with quad Picatinny rails in favor of a lightweight M-LOK rail.

Long one of our favorite AR-15 manufacturers, I’ve run Daniel Defense guns for years now, and they’ve proven their reliability time and time again.

The folks at Daniel Defense were kind enough to send me one of their DDM4s to spend some quality time with, which you can read more about in our DDM4 V7 review.

Durable Reliability

Daniel Defense is a fan of heavy phosphate coatings and hardened steel gas blocks, which gives their AR-15 rifles a one up on the competition when it comes to durability.

I’ve put a few hundred rounds through this test rifle, and it hasn’t complained once.  Beyond reliably chewing though Sellier & Bellot 55 grain M193 like a champ, the DDM4 spits brass at a near-perfect 4 o’clock from the shooter. It’s so consistent I can hear casings landing on one another behind me after a few rounds. It’s just a remarkably well-tuned rifle.

Availability continues to improve

Despite intermittent inventory & availability crunches (in-demand AR-15 manufacturers like Daniel Defense have not been immune to limited inventory), they’re still meeting demand pretty consistently, so if you can’t find the gun of your choice in stock sign up for their newsletter alerts and before long you’ll be at the front of the line.

The DDM4 is the smaller-caliber 5.56 NATO brother to the 7.62/.308 AR-10 DD5. And it’s an outstanding rifle and an example of the kinds of rifles that have made Daniel Defense a household name (of sorts); it feels like a high-end watch and runs, points, and performs as well as anything on the market today.

I find the DDM4’s grip a solid, pointable beast that offers more real estate than the Magpul MOE grip, and it has only recently been supplaneted by the Lead Star’s slimmer, stickier overmolded grip as my favorite.

I could go on and on about the DDM4 — it’s a great rifle and absolutely worth considering if you’re in the market for a premium AR. It’s hard to get too much of a good thing with Daniel Defense. They rarely disappoint, and the Daniel Defense DDM4 V7 holds that line impressively.

3. Runner-Up: Lead Star Grunt

What we liked:

• Lots of nice upgrade touches
• Light!
• Great trigger
• Quality furniture

What we didn’t:

• Can’t run a suppressor without replacing the handguard
• Muzzle brake is “capital L” Loud

Few AR-15s have impressed me in the pure “bang for the buck” category as the Lead Star Grunt. It’s not attempting to re-write the book or change the game in any sense, but Lead Start has really packed a lot to like in a sub-$1,000 rifle that will go bang every time you pull the trigger.

All the Upgrades

Lead Star may be familiar to the competition set, they’ve been cranking out precision-focused PCCs for some time, and their entry into the world of full-bodied rifles benefits from their precision PCC experience, letting the Grunt stand out amid the sea of 5.56 ARs available within a Benjamin of a grand.

If the Golden Age of 5.56 AR-15 rifles is truly upon us, the Grunt surprised me on a few fronts. The first is just how light and nimble it feels in hand. From the full-length 17-inch handguard to what is now my favorite AR grip (displacing the DD DDM4), everywhere I turned the Grunt over-delivered — especially for what is typcally considered a mid-tier rifle.

The Grunt being Lead Star’s entry into the (hyper-competitive) world of home defense, duty, and range rifles, it’s competing with a lot of options, but there are a few touches that helped the Grunt stand out.

It’s incredibly soft shooting — even with rapid firing — thanks in part to Lead Star’s unique muzzle brake, which leans on their 9mm brake design, using ports on top of the brake in addition to a pre-chamber to help keep muzzle rise to a minimum and extending their innovative approach to controlling a PCC to world of the 5.56 rifles.

Another area that impressed me was the trigger — it’s a slender girl, with zero — like zero zero — uptake. Super snappy six pounds in weight and breaks when you intend it to. Straightforward reset and predictable as can be. Just a delight.

This being my first time with a Lead Star AR-15, I was incredibly impressed and thought it would clearly make a solid go-to AR for a beginner or seasoned enthusiast.

Shortcomings

The Grunt was great on a lot of fronts, but I didn’t appreciate that the handguard, while lovely, runs out under the muzzle brake, preventing me from testing this with a suppressor.

That fact was made doubly painful by the muzzle brake itself, which — while effective — is supremely loud. This rifle will make you few friends at the range.

4. Best M4 Build: FN M4 Carbine AR-15

What we liked:

• US military-grade
• Deep AR expertise
• Standard service rifle of the U.S. Army
• Chrome lined barrel

What we didn’t:

• 16″ barrel is your only option
• Expensive

Best known for their SCAR-series rifles, FN has also been one of the biggest AR-15 manufacturers when it comes to making M4/M4A1 carbines for the US Armed Forces for the past two decades and consistently delivers thousands on open contracts every year.

Battle-proven M4/M4A1s

Yes, this is exact same rifle used by U.S. troops across the globe (giggle switch notwithstanding).

Their semi-auto M4 Collector Series guns, with a 16-inch, 1:7 chrome-lined, cold hammer forged barrel, is about as close as you can get to the Army’s standard rifle on the commercial market without talking to a recruiter. I’ve always appreciated FN firearms for their attention to detail and build quality, and the M4/M4A1 from FN holds that line beautifully.

5. Springfield Armory Saint Victor 5.56 AR-15

What we liked:

• Fantastic bang for the buck
• Solid upgrade over base SAINT rifle
• Nickel boron-coated flat-faced trigger makes for smooth, consistent pulls
• Smooth-top handguard makes it comfortable to use without gloves

What we didn’t:

• Tough to get your hands on one
• Short rail up top

From the M1A/M14 to the AR

Cleverly taking on the old U.S. Army’s defunct Springfield Armory name in the 1960s and making a name for themselves with semi-auto M1A variants of the classic M14, Springfield Armory, Inc. has been around the block when it comes to ARs and is now one of the go-to AR-15 manufacturers for many people thanks to their mix of approachability, quality, and price competitiveness.

An improvement over the base SAINT rifle

The Saint Victory builds on SA’s impressive SAINT semi-automatic rifle with serious attention to detail, a full-length 15″ M-Lok riddled handguard, mid-length gas system, a nickel boron-coated flat-faced trigger right out of the box, and a B5 SOPMOD stock that incorporates a QD sling mount and ergo cheek weld.

6. Also Great: Colt Law Enforcement 6920 Carbine AR Rifle

One of the original AR-15 manufacturers, Colt has certainly not abandoned American’s Rifle. Colt’s baseline M4 series gun, the LE2920 is one of the most encountered AR-15 rifles in the trunk of police cars from coast-to-coast.

Something of an old-school semi-automatic rifle, it has classic rounded handguards which can put a crimp in the plans of those who want to hand a dozen accessories from their gun, but the LE6920 screams “Mil-Spec” with its 16-inch cold hammer-forged barrel, fixed front sight, and Magpul MBUS BUIS.

7. .308 Pick: Ruger SFAR

Specs

• Caliber: .308/7.62 NATO
• Barrel Length: 16.1 inches (carbine); 20-inches (rifle)
• Overall Length: 34-37.25 inches (carbine); 38-41.25-inches (rifle)
• Weight: 6.8 pounds, unloaded (16-inch carbine); 7.3 pounds (20-inch rifle)
• Magazine Capacity: 20+1 standard SR-25 pattern.

What we liked:

• Ruger has delivered when it comes to a light AR-15-sized carbine that comes with the ability to fire the much more ballistically satisfying .308 Winchester.

What we didn’t:

• The innovative series of venting holes in the upper receiver, barrel extension, and bolt carrier leave the user with a very dirty rifle, especially when using a suppressor, while the factory-installed muzzle brake is sure to make no friends on the range– particularly when shooting indoors

Billed not as an AR-10 but rather a Small Frame Autoloading Rifle in .308 that is nearly the same size as a traditional 5.56 caliber AR-15, Ruger’s SFAR is turning some heads.

Debuted in late 2022 as Ruger’s move to replace their 7.62 NATO/.308 caliber SR-762 piston rifle, the sub-7-pound/34-inch SFAR came in much lighter than the SR-762’s chunkier 8.6 pound/38-inch size while still offering the same 16.1-inch barrel. Ruger pulled off the tiny miracle via tweaks in the bolt carrier group and via trimming ounces wherever possible, such as cutting back on the top rail and going with an ultralight skeletonized free-floating handguard.

This gas-impingement actioned AR-15-sized .308 still offers an adjustable Magpul MOE SL stock and matching grip, a two-chamber muzzle brake to tame recoil, and a handguard slathered in M-LOK accessory slots. The 16.1-inch barreled carbine only has two short Picatinny rails on the top of the upper receiver and handguard while the 20-inch model runs a full top Pic rail but comes in at 7.3 pounds, unloaded.

For use with suppressors, the SFAR features a 0.750-inch 4-position rotary-regulator gas block to dial in the gas as needed to match functionality. Finally, it has five sling swivel QD cups. 

The safety selector switch and bolt release are on the left of the lower while the magazine release button is on the right– as with just about every AR-15. They work as advertised. The charging handle is ambi.

The SFAR in its 16-inch format is probably the lightest commercial .308 autoloader on the market other than the much more expensive POF-USA Revelation. The Magpul furniture is comfortable and easy to use without adding extra weight.

Firing the 16-inch carbine on three different range days with an assortment of 500 hunting, military surplus, and target loads, I found the SFAR to run 400:400 without a suppressor mounted. However, when the suppressor was mounted (we used a Dead Air Sandman-S), things went off the rail until I experimented and dialed in the gas regulator to match the ammo.

The SFAR ships sans sights but has a top Picatinny rail on the upper receiver and handguard for optics, a red dot sight, and/or bolt-on irons.

Both SFAR models ship from the factory with the Ruger Elite 452 trigger that delivers a smooth, crisp 4.5-pound 2-stage trigger pull. The rifle is also compatible with standard AR-15 packs which means it can be easily swapped out.

I found the SFAR to be almost sub-MOA accurate with match loads from the bench at the 100-yard mark. This stretched as I moved targets and switched to milsurp loads but the carbine was still capable of hitting gongs out to 500 yards.

The SFAR is compatible with mil-spec AR-15 trigger groups, receiver end plates, charging handles, pistol grips, and adjustable stocks– which means you can switch up just about anything you want outside of the barrel, BCG, handguard, and receivers. 

8. Also Great: S&W M&P 15 Volunteer XV Pro

Back when revolvers were the main game in handguns, Smith and Wesson never tried to put Colt underwater by over-building their guns, but they did offer wheel guns that brought 99% of what Colt did to the table and for less money.

About a decade ago Smith and Wesson applied the same concept to the AR-15 by bringing their M&P15 line to market.

Priced affordably, they hit all the high points you look for in a quality AR in the sub-$1,000 price range. The M&P-15 is a great rifle that punches way above the mid-tier pricing, but their new M&P 15 Volunteer XV Pro really impressed me. This isn’t your ordinary AR-15.

The new Volunteer series from S&W is designed for competition and performance right out of the box. S&W partnered with some larger named brands to build an AR-15 with high-quality parts for those competitive shooters who want a reliable and accurate gun to shoot.

The XV Pro has a 16-inch 5.56 NATO barrel with an internal and external Armornite finish. The 15-inch M-LOK forend is made of aluminum to cut some of the weight out of the gun. The rifle has a mid-length gas system, and the barrel is topped off with a Primary Weapons Systems 556 muzzle brake, which really helps with control if being a touch loud.

One of the best features is the ambidextrous Radian Raptor charging handle for easy left or right-handed manipulations — it’s so easy to manipulate and looks fantastic.

S&W also outfitted the rifle with a flat-faced trigger, 2-inch M-LOK rail sections included, a B5 Systems P-Grip 23 pistol grip, and a B5 Systems SOPMOD stock.

The level of detail Smith & Wesson put into developing this rifle to be comfortable and competitive doesn’t go unnoticed. Simply top the gun off with your favorite LPVO, and you’re ready to race.

The pistol grip is a nice touch that gives most shooters a more comfortable grip angle as it comes more naturally. S&W also includes Williams Gun Sight Company Folding Sights, which I highly recommend keeping on the gun as backup sights if anything were ever to fail.

I found the gun sub-MOA accurate with good-quality ammunition straight out of the box.

9. Budget Pick: Anderson MFG AM-15 Rifle

Kentucky’s Anderson Manufacturing — lovingly referred to as the “Poverty Pony” in AR circles — is well known for lowers that cost less than a dinner for two. Still, their complete rifles are also solid performers. They manufacture all their components in Hebron, Kentucky, which helps them pass the savings onto you.

Their AM-15 is a fantastic budget AR is an inexpensive rifle with a 16-inch 4150 Chrome Molybdenum Vanadium Steel barrel that ends in an A2-style birdcage.

Despite what many folks would consider a “low expectation” rifle, the AM-15 runs a forged aluminum receiver that has been anodized, and the 1-8 twist barrel is parkerized, making for a gun that will hold up well over time. Some of the more subjective aspects — like charging handle feel — aren’t as polished as more high-end guns, but the Anderson is a reliable firearm that may very well win you over in time.

This rifle is a great choice for those who already have an optic picked out, as it includes a flat-top rail on the upper.

One thing I would like to see is some FSB, as the AM-15 does not have a front sight, but if you’re running an optics, it’ll do the trick. Also, the drop-in handguard does not have accessory rails, a common reality with sub-$700 ARs.

10. .223 Wylde Pick: Aero Precision AR15 M4E1 223 Wylde

Aero Precision almost certainly has the most receivers in circulation, and Enhanced Series Upper Receiver is incredibly popular. Their complete rifles are just as reliable and impressive.

This Aero M4E1 is chambered in .223 Wylde, which gives you the option of running 5.56 NATO or .223 Rem. The 16-inch barrel has been bead blasted and is made from 416 stainless steel, and when paired with the low profile gas block and a mid-length gas system, runs as smooth as rifles costing considerably more. It’s a fun rifle to shoot.

The receiver is Aero’s Gen 2 lower, which boasts a flared magazine well and has a tension screw to keep the play out of the upper and the lower. I would have preferred the inclusion of iron sights and– given the flexibility of the .223 Wylde to shoot the longer-ranged .223 Remington — a muzzle brake of some kind, as the A2 feels out of place with the rest of the rifle’s build quality.

The addition of the Magpul STR Stock is great, as you get both a comfortable comb angle and storage for things like batteries to keep your optics running.

The M4E1 is set up to be a perforant hunting rifle, so a scope on top of the ample Picatinny rail would be more appropriate. The lightweight M-LOK handguard keeps weight down while providing room for all the accessories you could want to take into the field.

11. Also Great: Diamondback DB15 FDE Elite AR-15

This year’s Diamondback’s DB15 has been totally redesigned, and if you simply add up the price of the components they incorporated into the new gun it’s easy to see how much value they packed into their new AR.

The inclusion of the 1-8 twist 16-inch 4140 Chrome Molybdenum Steel barrel,  forged 7075 T6 aluminum upper and lower both cerakoted in flat dark earth, an adjustable Adaptive Tactical EX Performance stock, and one of the most aggressive muzzle brakes I’ve seen on a factory rifle in years, it’s easy to see that Diamondback aimed this rifle squarely at those of us who want to spend around $1,000 on an AR without the need to upgrade it. The new DB15 does that in spades.

Many AR enthusiasts are happy to spend $700-$800 on a base gun, and slowly add better components over time to build or customize the rifle. That’s not something you’ll need to do with this gun — you buy it from the factory with all the bells and whistles you want.

12. RECCE Rifle Pick: Sig Sauer M400

Given SIG’s recent spate of military contract wins, their M400 line of ARs benefits from both the duty pedigree and SIG’s commitment to innovation. The M400 line has a few variants, from the budget-friendly Tread to the premium SIG M400-DH3, but my personal favorite (and the one we’ve got a good 2,000 rounds through) is the SIG M400-SDI XSeries, which strikes a balance between the Tread and DH3.

The M400 SDI takes the familiarity of the Tread/AR platform and marries it to the DH3’s competition focus, giving you a rifle that brings competition performance in a common tactical design.

The M400 is incredibly reliable, and M400-SDI XSeries adds a ton of nice upgrades over the Tread — like fully ambidextrous controls, ambi charging handle, and most importantly the sweet 2-Stage Matchlite Trigger that breaks right around 3.5 lbs.

The M400 SDI is an awesome rifle, and while it’s not cheap — often in the $1,200-$1,500 range, the fit and finish is fantastic, making it one of the few fully assembled rifles I would buy.

In 1955 the Army was looking to replace its long-in-the-tooth service rifle, the M1 Garand, and were considering two alternative options – the Springfield T-44, which was little more than an updated version of the Garand, and the T-48 –  version of the 7.62×51 mm FN FAL.

ArmaLite, a subsidiary of the Fairchild Aircraft Company, produced a candidate rifle for consideration, with executive presidents Paul S. Cleveland and Richard S. Boutelle exploring innovative new ways to use the technology brought about by the aviation industry to create firearms.

Early Success

Their initial goal was to focus on creating sporting rifles for the commercial market with the hopes of catching the interest of the military leaders to generate DOD business.

Still, shortly after establishing the company, Armalite was invited by the U.S. Air Force to submit a rifle design to replace their survival rifle, which won the favor of Air Force top brass and ultimately became the MA-1 Survival Rifle.

The success of their work with the military prompted Armalite to abandon the commercial market and instead build guns for Uncle Sam.

The company’s top firearm designer, Eugene Stoner, worked with George Sullivan – both an Armalite founder and a chief patent counsel for Lockheed (who was also a life-long tinkerer working on some of his ideas in his own garage) and Chares Dorchester, one-half of Armalite’s founding duo, to create a 7.62 NATO-caliber battle rifle for an Army small arms test, the AR-10 (ArmaLite Rifle Model 10 – “Armalite Rifle” being the “AR” in “AR-15” – not “Assault Rifle” as is often erroneously claimed.)

This new design used a two-piece aluminum receiver, the latest technological advancements in plastics and alloys, and an action that incorporated a direct impingement gas system rather than some sort of piston.

It was also decidedly light at just under 7 pounds when empty.

The receiver could be made from lightweight aluminum because it locked into a steel extension that attached the barrel rather than directly to the receiver itself. Furniture was also crafted from futuristic plastics rather than the solid wood grips and forends that marched through the trenches of multiple World Wars.

The AR-15 Rises from the Ashes

While in the end, the Stoner’s rifle wasn’t adopted after those early tests — few were a fan of the charging handle design, and the Army elected to go with the more conventional T44, which entered service as the M14 in 1957 — Stoner’s direct impingement gas block design was soon modified. Scaled-down by ArmaLite engineers Robert Fremont and Jim Sullivan to use a 5.56mm NATO round and the AR-15 was born.

Likewise, the AR-15s of today have morphed away from the original 1960s bench line to keep up with the times, many incorporating a variety of M4 features.

M4 design features include the now-standard birdcage flash hider, 14.5-inch barrel, shortened handguards with rail support, improved feed ramps, flat-top receiver, and an adjustable length, six-position stock.

If you’re interested in digging into these differences further we compare both the AR-15 and M4 as well as the AR-10 vs. AR-15.

Battle-Proven Modularity

By its nature, the AR-15 is lightweight and modular.

The military has fielded various models of the platform over the years in both shortened “Commando” varieties as well as heavy-barreled rifles geared for precision marksmanship at longer ranges.

This has had the side benefit of allowing owners whose guns are “banned” under state gun laws to modify their AR to a compliant or “featureless” format that is still legal with little more than some research into basic AR-15 reviews or what AR-15 buying entails.

Massive Aftermarket

With the slate of aftermarket support, you can take your AR in whatever direction you want when it comes to colors, and accessories. and overall configuration.

Today it is estimated that more than 18 million such modern sporting rifles are in circulation among America’s gun owners, a figure that is perhaps underestimated but nonetheless points to how popular the AR platform has become.

This tremendous market means there are many fantastic manufacturers creating niche products designed for every need – everything from small brands knocking out updated mag releases to Magpul’s military-embraced furniture, there’s a product out there for every need.

Added to this are AR-15 and AR-9 style pistols, which are all just branches of the family that are increasingly in demand and generating new product innovations on the daily.

More than 5 Forges

A popular trope among the AR-15 community, as the market has exploded in the past 15 years and now includes dozens of top AR-15 companies along with scores of smaller ones, is that deep down inside, all the rifles have the same heart.

There is no “best budget AR-15” out there – even the top-tier ARs are all cut from the same aluminum cloth, so to speak.

This is because most manufacturers take pre-made aluminum forgings and, after milling them out to finished upper and lower receivers, add barrels, internal parts, and furniture to produce finished AR-15s.

The saying is that “all the AR receiver blanks come from just five forges,” setting up a strawman argument that all AR-15 upper and lower receivers are fundamentally the same when it boils down to it.

Brands & Manufacturers Add Value

There are a lot of pieces on any AR, and we’re not going to get into the weeds on barrel profiles, anodizing, gas systems, or anything that won’t *really* matter to most folks.

That said, there are some fundamental criteria that will help you get the right black rifle for you:

1. Quality receivers
2. The right barrel
3. Functional furniture
4. A trigger that feels right

1. Quality Receiver Construction

The fundamental thing to look for in a solid rifle receiver is the construction – specifically, the kind of aluminum used to craft the two piece AR receivers:

• 7075 aluminum’s primary attribute is its strength. It’s not as corrosion resistant as 6061, but 7075 has tensile strength on par with steel.
• 6061 aluminum offers a blend of durability and natural corrosion resistance. It doesn’t offer 7075’s strength, but it offers a more workable material that is often slightly cheaper.

Forged vs. Billet: Further, while forged receivers are standard in AR production, some gun companies make their own billet receivers in-house, milled from a raw block of aluminum.

Most billet receivers have thicker walls and are harder to get into a military spec due to the machining process behind them but are preferred by those using heavier rounds with a bit more spice, such as .350 Legend, .277 Wolverine, and 6.5 Grendel.

The upper receiver, of course, houses the heart and soul of the AR, the bolt carrier group or BCG. The BCG, in common direct gas impingement models, consists of the actual carrier itself– the largest part in which the rest of the components either ride on or attach to– the bolt assembly in the front, the gas key held to the top of the carrier with two screws, the bolt cam pin, firing pin, and firing retaining pin.

The typical bolt assembly further breaks down into the bolt itself, the ejector with its spring and roll pin, the extractor with its pin and spring, and a trio of gas rings.

Want to know how an aluminum blank becomes a receiver? Take a look at our deep dive into aluminum and ARs.

We’ve got guides covering the top AR uppers and best lowers for any AR build.

The Bolt Carrier Group

The upper receiver, of course, houses the heart and soul of the AR, the bolt carrier group or BCG.

The BCG, in common direct gas impingement models, consists of the actual carrier itself– the largest part in which the rest of the components either ride on or attach to– the bolt assembly in the front, the gas key held to the top of the carrier with two screws, the bolt cam pin, firing pin, and firing retaining pin.

The typical bolt assembly further breaks down into the bolt itself, the ejector with its spring and roll pin, the extractor with its pin and spring, and a trio of gas rings.

When the AR is fired, the gas system bleeds out a portion of the propellant exhaust via a gas port on top of the barrel. It feeds it back to the gas key atop the BGC, filling the chamber made by gas rings at the base of the bolt assembly, which forces the bolt carrier itself against the recoil spring.

That rearward motion twists the bolt on the cam pin, unlocking the chamber.

When the spring reacts to the bolt carrier, pushing it back into the battery, the bolt picks up the next cartridge in the magazine and pushes it into the chamber as the gas key realigns with the gas tube running atop the barrel, waiting for the next shot.

The process needs a tightly sealed and aligned gas system for this to work as advertised.

What to look for in a BCG

A good checklist to look for is in the material used, with 8620 steel being mid-shelf, 9310 and Carpenter 158 steel considered more top shelf, and those made of S7 tool steel the good stuff kept behind the counter.

This doesn’t mean that 8620 is garbage, as it is the baseline grade that is considered Mil-Spec, but keep in mind that better grades of steel will hold up longer.

BCG CertificationBCGs will also carry a certification, or at least they should, to show the bolt itself is high-pressure tested (for shock-resistance), shot-peened (for strength), and magnetic particle inspected (for integrity), tests listed as HPT, MPI, and SP. We cover some of the better BCGs around if you’re in the market.

2. The right barrel

When the AR-15 rifle was first introduced in the 1960s, the standard barrel length was 20-inches, and the 5.56 NATO caliber ammunition of the day was ballistically optimized for that span.

Today, loads such as M855 are widely available and still deliver optimally in a 20-inch or longer barrel for those interested in maximizing accuracy — say, for competitive shooting.

\Since the early 1990s, the widespread adoption of M4 style carbine barrels, which for military and LE using a shorter barrel at just 14.5-inches, had led to many common ARs today having a default barrel length in the 16-inch range.

This choice is backed up by extensive barrel-length studies that found the “sweet spot” for common 5.56 loads in this range, although standard-length (20-inch) barrels deliver more velocity, thus imparting more energy to the bullet.

Even with that, there are custom hunting and target uppers that stretch out to 24- and even 26-inches. Beware, though, when using the long boys as harmonics issues start to come into play since longer barrels by nature will have more vibration.

Short Barreled 5.56 Performance

On AR pistols, the minute the barrel length starts to plunge below 14.5-inches, 5.56/.223 ballistics will begin to rainbow downward, shedding velocity with every inch dropped in barrel length while adding to noise and muzzle blast.

Short-barreled SBRs and pistols in standard AR chamberings also suffer from extensive muzzle flash due to unburnt powder and have a reputation of being “rowdy” on the range.

They’re also subject to a number of gun control efforts that longer-barreled rifles don’t have to navigate. Nonetheless, manufacturers market 5.56 barrels as short as 4.75 inches in overall length, targeting home defense rifle builders and range toy enthusiasts who don’t fear a little hot gas for breakfast.

ARs range from 10-inch shorter barrels seen on AR pistols and SBRs to 24-inch long toms on some custom precision guns when it comes to barrel profiles.

Generally, weights will run from thin “pencil” types to heavy bull target barrels, with a sweet spot of around 16 inches being the norm — both as the minimum barrel length for a legal rifle and providing optimal ballistic performance for the 5.56/.223 round in most scenarios.

This is a good example of the modularity that makes the AR-15 so great.

What about barrel profiles?

Barrels also fall into three general “profile” types– lightweight, government, and heavy. Ironically, the hallmark of the early AR and subsequent AR-15 was a very thin barrel as the gun was developed by a company that was a subsidiary of a big player in the aviation industry, one in which every ounce mattered.

Barrel Material

Most AR rifles in circulation today have barrels made of 4140 CMV steel, which is fine for general use. Barrels advertised as Mil-Spec will usually be made of stronger MIL-B-11595-E CMV or 4150 steel. Premium match barrels will usually be 416/410 stainless steel.

• 4140 indicates the barrel contains 40% carbon content
• 4150 indicates the barrel steel has a carbon content near .50%

A black nitride finish is typically seen on entry-level barrels. It is a little cheaper than manganese-phosphate hard chrome, which can be found on nicer (see; more expensive) barrels, with the latter lasting longer, especially when using heavier bullets, and for those interested in preventing barrel whip.

A chrome-lined barrel adds life and wear resistance, but can add to the final cost. If you want more on AR barrels we go deep in our AR barrels explainer.

3. Functional furniture

Originally, the system Eugene Stoner developed for his Armalite rifle used fixed plastic or fiberglass handguards around his early AR designs’ thin, lightweight barrel continued for the first couple of decades of the AR-15/M16s life.

This was supplemented by two-piece handguards held in place with a cap and delta ring system and incorporated internal heat shields between the handguard and barrel to prevent melting in heavy use.

These days you have a few choices when it comes to handguards & furniture.

• Drop-in Handguards: So-called drop-in handguards, often with rail systems, started appearing in the early 1990s and offered a more up-to-date replacement for the old A1 and A2 style fore-ends. While they are lightweight and easily replaced if broken, the problem with these is that they attach to the barrel directly, affecting accuracy, especially as accessories are mounted.
• Free-float Handguards: More common today are free-floating handguards on the forearm, a feature seen even on AR pistols. Attaching to the barrel nut instead of the barrel itself, which allows for a truly free-floating barrel, free-floating handguards are often more modular than fixed handguards, dripping in Key-Mod or M-LOK slots for accessories (or running a full-length quad rail) and Pic rails for optics at the 12-, 3-, 6-, and 9-o’clock positions.

Further, since the barrel is free from the furniture, its harmonics are not affected by the handguard, aiding in maintaining accuracy and heat resistance.

Handguard length on AR-style rifles typically varies with the length of the firearm’s gas system. For instance:

• Pistol length systems run 10-inches as pistols must have at least a 4-inch system
• Carbine gas systems run 7-inches
• Mid-Length gas systems are 9-inches
• Rifle-Length gas systems are 12 inches

Gas system length informs handguard length, which translates into:

• M4 handguards for carbines which are 7-inches long
• Mid-Lengths, which are between 9 and 11-inches
• Rifle-length handguards are generally anything over 12 inches

This is all before we get into the world of DI (Direct Impingement) vs. gas the piston system and the like. We dive way deep into gas systems with our explainer on the topic.

4. A trigger that feels right (for you)

The most encountered trigger type on AR-15s is the good-old GI “Mil-Spec” pack. A single-stage trigger that can vary between 5.5 and 8.5 pounds, they have a lot of “creep” on the take-up before they break but perform well enough, are cheap, and reliable enough for target practice.

Most standard lower parts kits, which include everything needed to get a stripped lower receiver in working order, include a GI trigger system. While effective, they can be irritating for those who prefer a more predictable trigger break.

Drop-in preassembled replacement trigger packs can easily upgrade ARs and provide a more repeatable trigger pull, replacing creep with crisp. A good example is the CMC Single Stage, which is offered in both 2.5-pound and 3.5-pound pull weights, which can be had for around $100.

Double stage triggers have a mechanical change to the hammer, sear face, catch, and springs that creates a pull cycle that includes first a light take up to bring the catch to tension, then a clean release when the trigger breaks. These triggers are smooth and, while a little costly at about $200-$300, are worth it when precision accuracy and long-range shooting are concerned.

Another thing to keep in mind on trigger packs is the choice between more common curved triggers and flat-faced triggers.

While some drop-in packs will come with flat-faced triggers installed, companies such as Bullmoose offer flat-faced replacements for curved triggers that are compatible with the Mil-Spec parts kits.

Compared to precision bolt guns or collector pieces like Al Capone’s favorite .45 Auto an AR is decidedly affordable.

• $700-$1,000. Entry-level, budget rifle options that still offer solid quality control will often cost less than $700 and generally keep under the $1,000 price point. For that level of investment, you’ll get a perfectly functional AR, often with MOE furniture and some solid BUIS.
• $1,000-$2,000. Moving into the middle tier gets you into the sub-$2,000 range, which often includes lighter materials, more custom furniture, and one or two bonus features.
• $2,000 and Above. Spending more than $2,000 will get you a premium AR that often includes piston-driven systems which run cleaner and cooler than a standard Direct Impingement system.

Entry-Level Brands

• Palmetto State Armory
• Rock River Arms
• Springfield
• Stag
• Anderson

Mid-Range

• Aero Precision
• Colt
• Ruger
• Sig Sauer
• Smith & Wesson

Premium Brands

• Bravo Company
• Daniel Defense
• Larue
• Lewis Machine & Tool
• LWRCI
• Noveske
• Patriot Ordnance
• Windham

Given the size and scope of the AR world and its standing as a consistent target of ever-evolving gun laws, finding the right AR-15 for you can be intimidating, especially when you’re looking for your first AR, starting down the long road of building your own from an AR build kit, or just concerned about the ever-evolving world of gun control.

In the end, whenever one of my friends wants recommendations for choosing an AR-15, I always recommend doing your homework, spending some time at your local gun store, and making sure your rifle is designed for your needs. The modular design of the AR means you can build a big game hunting rifle, one for long-range precision, a competition gun, a home defense gun, something for close-quarters combat, or anything in between.

I recommend buying a complete rifle, spending time at the gun range with it – then getting another!

1. NRA Museum, Colt AR-15 Rifle
2. National Park Service, U.S. SUBMACHINE GUN XM177 “COMMANDO”
3. NRA Museum, Guns of Vietnam and Desert Storm
4. Defense Standardization Program, FAQs
5. Accurate Shooter, Barrel Rifling Process
6. Nathan Schueth, 4150 Carbon vs 416-R Steel
7. Otai Steel, 9310 steel vs 8620
8. Stag Arms Blog, Commercial vs. Mil-Spec Buttstocks
9. Peter Luff, Troops in Afghanistan get new lightweight rifle magazines
10. Howard Precision, Difference Between 6061 and 7075 Aluminum
11. FBI.gov, NICS Background Checks By Month/Year
12. Wikipedia, Ammo Shortage in the U.S.
13. NPR, Kyle Rittenhouse Trial In Kenosha Killings Delayed Until November
14. NRA Blog, How to Pick the Right Round For Your AR-15 Barrel
15. SADJ, Barrel Length Studies in 5.56 NATO Weapons
16. Ballistics by the Inch, 5.56 Ballistics by Barrel Length
17. KAK Industry, 4.75″ AR Barrel