The Best AR-15 Rifles

What is the right AR-15 for you?

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. Home defense, distance shooting, 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.

Back in the 1960s and 70s, Colt was the only game in the AR-15 market.

This started to break in the 1980s as others like Eagle, FN, and Olympic entered the field. Today, just about every modern rifle maker who produces semi-autos will have an AR of some sort in their catalog. We spent some time with a few of the better ones floating around.

Quick List: The Top AR-15 Brands

1. Palmetto State Armory PA-15

Performance Scorecard:


What we liked:

  • Solid availability
  • Great price point
  • 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

A quality (and available) workhorse AR

best ar 15 - PSA PA-15, side view
While the PSA PA-15 doesn't have the fit and polish of other ARs, it doesn't come with the premium price tag either.

Palmetto State’s PA-15 mil-spec AR-15 uses standard components, and pairs a 4150 Chromoly 16 inch barrel with a classic A2-style flash hider and 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 there’s generally always a few in stock, which is a rarity given the surge in demand for ARs (and firearms in general) over the past year.

We really appreciated the classic look and feel of the A2 birdcage flash hider & nitride-coated, chrome moly vanadium barrel. The 1/7 twist is just right too. Who doesn't love the classic front sight paired with the M4 cutout? You know, in case you need to mount an M203 grenade launcher.

Flaws worth noting

Holy mil-spec Batman. The pride of West Columbia S.C.

Our main issue with the PSA is its carbine-length gas system paired with the 16-inch barrel which tends to over-gas the gun.

Sure, you’ll be able to power through the cheapest ammo available (and given recent trends *cheap* is probably the wrong word), but we 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.  

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.

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

All-in-all PSA continues to use its massive component infrastructure to deliver fun, high-quality products, and their PA-15 is no different. Sure, there are higher quality, better-designed ARs out there, but for a first AR or a 5th, we think the PSA hits the sweet spot of value and performance.

Getting rounds in on the PA-15

2. Daniel Defense DDM4

Performance Scorecard:


What we liked:

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

What we didn't:

  • Price
  • Availablility

A top-tier AR if there ever was one

The company that made AR rail systems popular has been one of the best AR producers now for a generation. Their DDM4, especially the V7 series gun, uses a government profile barrel and is dripping with M-LOK slots. We’ve run Daniel Defense guns for years now, and they’ve proven their reliability time and time again.

Best AR-15s - DDM4 Close Up
Up close and personal with the DDM4

Heavy coatings for max durability

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.

best ar 15 - daniel defense rail
Close up of the DD rail. We found mounting accessories was a pleasure with the DD.

Availability... about that

Despite the current inventory & availability crunch (Daniel Defense has 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. 

best ar 15 - daniel defense BGC
Note the DD stamp on the BCG -- this kind of care is a hallmark of DD ARs

3. FN M4 Carbine

Performance Scorecard:


What we liked:

  • FN’s M4 carbines are military-grade
  • Deep AR expertise 
  • Standard rifle of the U.S. Army

What we didn't:

  • 16″ barrel is your only option
Best Ar-15s - FN M4 Carbine
My personal FN M4 rifle, side view. Sling loop, vertical grip, Knights Armament quad-rails? Check, check check.

Best known for their SCAR-series rifles, FN has also been one of the biggest players when it comes to making M4/M4A1 carbines for the military 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).

best ar 15 - FN M4, rail covers
KA rail cover forge mark. Press the metal tab to remove the cover.

Their semi-auto M4 Collector Series guns, with a 16-inch, 1:7 chrome-lined barrel, is about as close as you can get to the Army’s standard rifle on the commercial market without talking to a recruiter.

best ar 15 - FN M4, rail cover removed
Pressing the tab on the rail cover enables you to slide it off, revealing the rail space beneath.

4. Springfield Saint Victor

Performance Scorecard:


What we liked:

  • Solid upgrade over base SAINT rifle
  • Flat-faced trigger 
  • Smooth-top handguard

What we didn't:

  • Tough to get your hands on one
  • Lack of Picatinny rail up top

From the M1A/M14 to the AR

The SAINT rifle (top) as compared to the pistol version (bottom). The SAINT series is available in both rifle and pistol formats, in case you feel like collecting them all.

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 come to ARs.

No need to bust out the punches - the SAINT comes with a flat-faced trigger.

An improvent over the base SAINT rifle

The 15-inch handguard runs almost the full length of the 16-inch barrel, and features a smooth top, eliminating the Picatinny rail of previous versions (no gloves needed!) but keeping all the M-LOK mounting slots & Springfields proprietary 2-part muzzle brake.

The Saint Victory builds on SA’s impressive SAINT rifle with a full-length 15″ M-Lok riddled free-floating 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. 

Also new in this latest version: a QD end plate. Let your sling dreams run wild!

5. Colt LE Carbine

Performance Scorecard:


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.

best ar 15 - Colt LE AR, gas system
Beneath the handguards we see the mid-length gas system.

Something of an old-school design, 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 barrel, fixed front sight and Magpul MBUS BUIS.

best ar 15 - Colt LE AR, bolt markings
Bolt markings on the Colt, which designate the possible sub-contractor who produced the bolt itself.


Performance Scorecard:


Specializing in the black rifle game, LWRCI is seen by many as an upper-tier builder.

best ar 15 - LWRC, barrel fluting, flash hider
The barrel fluting on the IC DI is almost worth the price of entry alone.

Their IC DI series guns cost a bit more than some of the competitors but the build-quality, to include fluted spiral barrels with free-floating rails, is hard to beat.

best ar 15 - LWRC, charging handle
Even the charging handle on the IC impresses with its build quality
best ar 15 - LWRC, free floating fore-end
The free-floating rail and fore-end give the LWRCI a really high-end, quality look.

7. Ruger SR556

Performance Scorecard:


Long known just for pushing their Mini-14s and Ranch Rifles as an AR-15 alternative for the past 40 years, Ruger recently decided to grab a slice of that sweet, sweet AR pie directly with their SR556 series.

AR15_Ruger SR556
The SR556 and its classic forward assist.

With deep pockets, well-established CNC factories, and good company philosophy, the folks of the Black Eagle have done a good job in playing catch up and the Ruger AR 556 is both decent and decently priced.

The handguard offers loads of M-LOK slots and topped with a Picatinny to accomodate both BUIS and an optic.
Who doesn't love a stamped BCG?

8. Sig Sauer M400

Performance Scorecard:


While Sig will gladly sell you a high-end rifle that costs well above the $2K mark, they also make a gem known as the M400 which brings quality Sig Sauer features such as a Magpul SL-K stock, polished trigger, ambi controls and a 16-inch stainless barrel for a price point that is much more affordable for your average Joe Beercan.

AR15_Sig Sauer M400-2
The M400 is classic Sig -- quality & care from every angle.
AR15_Sig Sauer M400-4
The upper's Picatinny rail give you plenty of room for the optic of your choice.
AR15_Sig Sauer M400-5
The mid-length gas system makes for a softer-shooting rifle.
AR15_Sig Sauer M400-6
Sig's adjustable gas block isn't shopped out.
AR15_Sig Sauer M400-7
The three-prong flash hider offerse both form and function.
AR15_Sig Sauer M400-10
All your range buddies will know when you're on the line.

9. Smith & Wesson M&P-15 Sport

Performance Scorecard:


Back when revolvers were the main game in handguns, Smith & 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.

AR15_Smith & Wesson M&P-15 Sport
The front end of the M&P can feel a little heavy due to the barrel profile.

About a decade ago they 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 basic AR.

AR15_Smith & Wesson M&P-15 Sport-1
A slimmer barrel profile, like this from an M4 would balanace the rifle better.
AR15_Smith & Wesson M&P-15 Sport-2
Cracking open the handguard.

10. Windham CDI

Performance Scorecard:


Rising from the ashes of Bushmaster, Windham Weaponry builds great ARs and their CDI gun is no exception.

AR15_Windham CDI
Magpul furniture included.

Using a 11595E steel barrel with a 1:9 twist, a free-floating M-LOK aluminum rail system, adjustable stock and Magpul furniture, they are ready to go right out of the box.

AR15_Windham CDI-2
The factory CDI includes a hand stop -- nice touch!
AR15_Windham CDI-3
The free-floating handguard gives you lots of room for goodies without infringing on accuracy.
AR15_Windham CDI-4
Windham's custom muzzle brake.

History of the AR-15

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.

Richard S. Boutelle and the AR-10 Rifle
Richard S. Boutelle, president of the Fairchild Engine and Airplane Corporation, holds a Fairchild Armalite AR-10 battle rifle.

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, but 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.

AR-15 vs M4 - Cover
This early Colt AR-15 model was tested by the U.S. Army in 1962. The service eventually adopted the carbine as the M-16

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

Stoner’s Modular AR-10

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 the bolt 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 AR-10 wasn’t adopted after those early tests — few were a fan of the charging handle design, and the Army elected to go with a more traditional design that was developed by the military in-house — Stoner’s direct impingement gas block design was soon modified and scaled-down by ArmaLite engineers Robert Fremont and Jim Sullivan to use a 5.56mm NATO round and the AR-15 was born.

AR-15 vs. M4 vs AR-10

The standard Colt AR15 M01 gas-operated, select fire, assault rifle with OD green furniture.
The standard Colt AR15 M01 gas-operated, select fire, assault rifle with OD green furniture.

With the patents and rights to the new gun purchased from ArmaLite by Colt, the U.S. Air Force became interested in the futuristic lightweight carbine and began buying a select-fire version of the rifle by 1961, a move the Army and Marines soon followed, with their AR-15 version of the gun later designated as the M16 in 1963.

Soon after, the rifle entered the consumer market as early as 1966 with Colt selling it as the semi-automatic AR-15 Sporter, which cost $194 when first introduced, a figure that adjusts to $1,500 in today’s dollars.

Best AR-15s - Colt's 1966 consumer ad
Colt Firearms debuted the AR-15 on the consumer market in 1966, a model later referred to as the SP-1. Colt still makes select-fire variants for law enforcement and military use as well as semi-auto ARs for the consumer market.

Since the gun’s debut during the Vietnam War, the military has gone through several generations of Mr. Stoner’s carbine, moving to the M16A1, XM177E1, M16A2, CAR-15, M16A4, M4, and M4A1, among others. 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.

Likewise, the AR-15s of today have morphed away from the original 1960s bench line to keep up with the times.

AR-15 VS M4 - Direct Comparison
A direct comparison between the AR-15 and the M4 (Air Force version of the XM177)

Why the AR-15 Today?

AR-10 vs AR-15 - Comparison
Comparing 2 cailbers of the same AR brand

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.

best ar-15 - rail and handguard
The AR platform is designed to accommodate basically any rail system under the sun.

Eventually, they dropped the carry handle for a flat-top to accommodate optics and added accessory rails along the handguard for everything from foregrips to lasers.

This helped the consumer “black rifle” market evolve to become the beast it is today. 

The modular design of swappable AR-15 parts — like being able to swap out entire upper receivers for different roles or at different price points,  moving to a side-charging upper, adding a Picatinny rail, muzzle device is a remarkable trait. 

Unfinished and finished AR-15 Lowers
Finished and unfinished AR-15 lowers. The base of the beast.

Changing from a compact pencil 16-inch barrel to another with a 20-inch HBAR will take under a minute, and you can easily change out buttstocks, pistol grips, and handguards with no more assistance or prior experience needed than a YouTube video, has made the AR-15 the equivalent of “legos for grown-ups”. 

AR handguard & barrel lengths
AR barrels & handguards are available with a dizzying assortment of lengths, mounting systems, and chamberings.

One Lower to Rule Them All

Couple this modularity with the fact only the lower receiver is serialized and you can build many ARs from a single lower without any additional paperwork. You 

Building an AR to match your needs – either a personal defense pistol in .300 Blackout and paired with a red dot sight, .223 Wylie rifle, or long-range upper like the Valk to bring out the potential in your big game hunting, AR-15 rifles give you a platform that can get it all done.

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

best ar-15 - handguard
With the slate of aftermarket support, you can take your AR in whatever direction you want when it comes to colors, 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.

5 Forges!

Ling Range AR Uppers - forge mark
The splintered "A" forge mark seen on this FN M4 upper receiver shows that the raw component was made by Anchor Harvey Aluminum, a popular forging company that is widely used in the firearms industry by gun makers large and small. It is, however, still an FN upper as the latter company machined and finished it into final production.

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 best AR-15s 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.

9mm AR9 Uppers - Unfinished Uppers
Unfinished AR lower and upper forgings

Brands & Manufacturers Add Value

This is wrong in several ways, as there dozens of forges– not “just five” although some forges do produce blanks for numerous AR makers at the same time– and it takes a good bit of work for quality producers like Aero Precision, River Rock Arms or Bravo Company to move from the basic aluminum blank to a finished product.

Each gun maker utilizes its own engineering specs and practices, finishing, and QC methods to craft a final product.

This tooling, such as making sure the bolt carrier group is open enough, the threads for the receiver extension/buffer tube are square, the lugs and pivot holes are within spec, and that flashing is cut away properly, is what makes a good receiver. We cover buffer tube kits and adjustable gas blocks if you’re into gunsmithing. 

Generally, speaking AR manufacturers can be broken down into broad categories:

Value Brands (> $1,000)

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

Middle-Tier (> $2,000)

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

Premium (< $2,000)

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

Construction Matters

The fundamental thing to look for on a receiver is not the forge marks but the construction,.

  • 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. Doesn’t offer 7075’s strength, but it offers a more workable material.

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 Valkyrie and 6.5 Grendel.

Polymer and composites have been used in lowers by companies like Omni and New Frontier, which is a whole different story.

Mil-Spec is Mil-Spec, Bro

buffer tubes - mil-spec vs commercial
Mil-spec vs commercial buffer tubes

Barrel lengths, twist rates, & materials

One of the biggest appeals of the functionality of the AR-15 platform is that, if all of the components are made to a single specification, they interchange, no matter who assembles the gun. Feed ramps, iron sights, triggers, and gas blocks all just work.

Said baseline specification is typically that set by the U.S. Army, which is just referred to as “Mil-Spec” in the industry. 

Keep in mind this spec itself has evolved over time, with what was considered “in-spec” for 1965, naturally no longer the standard today. Of course, none of these mill spec requirements obviates the need for regular care and feeding by way of cleaning and repair.

Mil-spec as a Minimum

Current standards for the M4 are what is generally considered to be the *minimum* acceptable for use, with many AR makers today concentrating on making guns that are better than Mil-Spec, with tighter tolerances.

For instance, a standard Mil-Spec trigger on an AR will typically break anywhere between 6- and 8-pounds with a good bit of creep, which is fine for most uses, but crisp trigger packs and tighter single and two stage triggers by companies such as CMC, which are standard with some builds, break as low as 2-pounds.

Best AR-15s - This lead lapped, 1_7 416R stainless steel barrel
This lead lapped, 1:7 416R stainless steel barrel is ideal for use with 77-grain ammo.

The whole concept behind a rifle comes from the fact that such firearms use a “rifled” barrel rather than one that is smooth, such as in old school muskets or shotguns.

Optimal Twist Rates

Rifling in the U.S. is measured in the number of inches it takes to fully rotate a bullet moving down the barrel.

  • A 1:10 twist rate means that it takes 10 inches of barrel to impart a full spin of the projectile.
  • A 1:7 twist rate requires 7 inches of barrel to spin the same projectile.

Heavier bullets benefit from tighter twists

Bear in mind that a looser twist will benefit lighter bullets while heavier bullets will perform optimally with a tighter one. 

For example, in the world of ARs using .223 Remington/5.56 rounds a 77-grain bullet performs better from a rifle using a 1:7 twist than one with an old-school 1:12 rate, with the latter being better for light bullets such as 55-grain loads.

Today, 1:7 and 1:9 twists are common while 1:8 gives a better life than and is about the best all-around 55- through 77-grain.

Barrel Profiles

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

Generally, weights will run from thin “pencil” types to heavy bull target barrels, with a sweet spot of around 16-inches being the norm and giving 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. 

The variety of muzzle brakes and devices gives the AR enthusiast almost unlimited potential for optimization and customization.

Barrel Material

Most ARs 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 of 416/410 stainless.

A black nitride finish is typically seen on entry-level barrels and is a little cheaper than manganese-phosphated hard chrome, which is on nicer barrels, with the latter lasting longer, especially when using heavier bullets.

Bolt Carrier Groups (BCGs)

Best AR-15s - Bolt Carrier Group
A Bolt Carrier Group

Perhaps the most important part of the AR platform when it comes to performance and reliability is the construction of the Bolt Carrier Group or BCG.

As with many things black rifle, there are dozens of companies that spend big money developing the next, greatest BCG and will let you know all about it.

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.

BGC Certification

BCGs 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.

Gas systems & steel cases

Various gas system lengths
Gas systems by barrel length

The mystery of making Eugene Stoner’s original DGI gas system of operation work properly over the years has been muddled by follow-on generations of AR gas systems of various lengths to fix assorted issues. 

Shortcomings of the AR gas system

In a nutshell, the nature of using hot, spent gasses from fired rounds to cycle the action means the systems need maintenance (not something that was shared with the boys in Vietnam when the M-16 first made its debut.) It was famous for jamming from the littlest dirt. 

An under-gassed (or under-maintained) AR-15 will cause short-stroking of the bolt and result in jams or failures as well as the user taking brass to the face. A shortcoming like this cost far too many boys their lives on the front line when the forward assist turned a jam into a useless 1-shot rifle.

The AR gas system
The AR gas system

A properly gassed AR hums like a sewing machine and eject brass almost directly to the right of the gun’s port.

Over-gassed guns will kick brass well forward of the ejection port and lead to more fouling in the action, making the gun run dirtier (and taking more time to collect your brass if not using a brass catcher.)

JP Enterprises gas blocks
A collection of AR-15 gas blocks

Commercial AR-15s are often a bit over-gassed which gets a lot of grouching in online gun forums.

This is something that is needed to help blast out cheap Russian-made steel-cased cartridges (Wolf or Tula 

It’s also useful for ensuring cycling even in the face of poorly maintained AR-15s with loads of build-up.

Speaking of that Russian stuff, the main thing to remember on ammo selection besides bullet weight is to look for non-corrosive loads.

An adjustable gas block in place on an AR
A mounted mid-length adjustable gas block.

A lot of military surplus rounds, such as Eastern European and 1980s Chicom loads, were brought in to the U.S. for cheap and stacked deep but they used corrosive propellants and primers, something even the Russians have moved away from recently.

While you should always clean any gun after firing before returning it to storage (check out our AR-15 cleaning kit guide for recos) corrosive ammo will take an especially tough time on your chamber and breech face, leaving a rusty, crusty mess behind for those who failed to maintain their weapon.


Getting into the world of AR-15s can be intimidating, especially when your looking for your first AR or if you start down the long road of building your own from an AR build kit (which, depending on where you live, may save you a decent amount of change — we’ve heard horror stores of up to an 11% tax on long-guns. And you thought ammo was getting expensive!)

In the end, when choosing an AR-15, do your homework and make sure your rifle is designed for your needs – be it a big game hunting rifle, long-range precision, close-quarters work, or something in between. Buy a complete rifle, make it a good one – then get another!


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MICHAEL CRITES is el jefe around here. He has spent more than 30 years shooting, learning about guns, and collecting firearms old and new. He’s tried his hand at 3-gun, trap, and distance-shooting, but ultimately enjoys ringing steel in the back 40 of his farm. His mission is to make guns and shooting accessible for everyone, and American Firearms is a passion project to help make that a reality.

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