The upper receiver is the part of a gun that houses the chamber, firing pin, and ejection port. Because the upper contains the majority of your rifle’s moving parts, it has a huge impact on your gun’s performance. By replacing your upper, you can effectively have a brand new AR.
And unlike the lower receiver, the upper isn’t serialized. This means you can modify your AR, even change the caliber, without needing to go through a NICS check for a complete second rifle.
Because this is such a popular upgrade, we’ve put together a list of the best AR-15 uppers that money can buy. We’ve made our selections based on quality, durability, and ease of installation. We’ve also considered price, so you’ll see a wide range of prices.
Finally, we’ve included a variety of designs, from complete kits to strippped uppers to SBR-style uppers and even alternative calibers.
Let’s begin!
20 Best AR-15 Uppers
The DPMS Oracle comes pre-assembled with a 16-inch barrel.
Key features:
- Complete AR upper and barrel
- Flat top design with Picatinny rail
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 16-inch barrel with flash suppressor
The DPMS Oracle is a pre-assembled upper receiver, complete with all moving parts and a 16-inch barrel. Attach it to a mil-spec lower receiver and add a buttstock, and you’ve got yourself a complete AR. The Oracle is chambered in 5.56mm NATO, which also allows you to fire standard .223 ammunition with no issues.
This assembly uses DPMS’ lightweight barrel, and an anodized aluminum receiver frame. This makes it significantly lighter than original, mil-spec parts. Of course, thinner, lighter metal is less durable, so the Oracle is better suited for plinking than for rugged field use.
The receiver parts are coated with teflon, for smooth, easy operation, and all parts are covered by DPMS’ lifetime manufacturer’s warranty. Make sure to clean and oil the Oracle thoroughly — the barrel is chrome-moly steel, but it’s not chrome lined, so it’s still susceptible from corrosion due to powder residue.
Pros:
- Pre-assembled for easy installation
- Lightweight
- Teflon-lined receiver
- Lifetime manufacturer’s warranty
Cons:
- Barrel is not chrome-lined
This smooth-operating, lightweight upper receiver is ideal for plinking.
2. Aero Precision M4E1
The Aero Precision M4E1 includes an extended Picatinny rail handguard.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 14.5 or 16-inch barrel with flash suppressor
- Mid-length gas system
The Aero Precision M4E1 comes in a dizzying number of variants, and we’ll be talking about a few of them in this article. We’re beginning with the standard, 5.56mm NATO version, which can also fire .223 rounds without any issues.
The M4E1 arrives pre-assembled, with either a 14.5-inch or 16-inch barrel. The only thing you’ll need to do is install a bolt/carrier group and charging handle. Both lengths include an extended, 12-inch or 15-inch Picatinny rail handguard. They also both include a flash suppressor. Be careful with the 14.5-inch variant; you’ll need to have the flash suppressor pinned and welded for it to be legal for civilian use.
The reason we’re such big fans of the M4E1 — and the reason we’ve reviewed a few different versions — is the mid-length gas system. Most AR-15s with barrels shorter than 18 inches utilize a carbine-length gas system, which means that the gas port is located 7 inches down the barrel. The mid-length gas system has a gas port 9 inches down the barrel, which provides just enough delay to reduce jamming to a minimum.
Pros:
- Smooth, reliable cycling
- Relatively easy assembly
- Lifetime manufacturer’s warranty
Cons:
- Does not include bolt/carrier group and charging handle
This assembly is one of the most reliable on the market.
3. Yankee Hill Machine Black Diamond Specter
The Yankee Hill Machine Black Diamond Specter includes four Picatinny rails for mounting all your accessories.
Key features:
- Complete AR upper and barrel
- Flat top design with four Picatinny rails on an extended handguard
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 16-inch barrel with flash suppressor
- Mid-length gas system
The Yankee Hill Machine Black Diamond Specter arrives fully assembled, ready to install on any mil-spec AR-15 lower receiver. It’s chambered for 5.56mm NATO, and is also compatible with .223 cartridges.
The Black Diamond Specter features a 16-inch, chrome-lined barrel with a flash suppressor. The top Picatinny rail extends continuously from the back of the receiver to the end of the handguard, with three additional rails on the bottom and sides of the handguard. The handguard itself is 9.675 inches long on the standard variant, and 12 inches long on the Black Diamond Specter Xl.
Like the M4E1, the Black Diamond Specter utilizes a mid-length gas system for more reliable cycling. However, it utilizes a low profile gas block to make room for the handguards. Between this and full assembly, it’s fairly pricey.
Pros:
- Quick, easy installation
- Smooth, reliable cycling
- Room for plenty of accessories
- Lifetime manufacturer’s warranty
Cons:
- Pricey
This is a top-tier upper receiver that’s built for use in the field.
4. Aero Precision M4E1 – .223 Wylde
The Aero Precision M4E1 in .223 Wylde features a mid-length gas system and a finely-machined chamber.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- .223 Wylde chamber
- 16 or 18-inch barrel with flash suppressor
- Mid-length gas system
The Aero Precision M4E1 in .223 Wylde is engineered specifically for target shooters. Its chamber is finely machined for precision feeding of the .223 Wylde target round. It will also fire standard civilian .223 cartridges, but not 5.56mm NATO cartridges. The NATO rounds have a more powerful charge, and the higher pressure can damage the chamber.
This upper receiver includes a 16 or 18-inch barrel, with a flash suppressor, a 12-inch handguard, and a full-length Picatinny rail. It requires a bolt/carrier group and charging handle, so you’ll need to either re-use parts from your old receiver or purchase new ones on the aftermarket. Other than that, the M4E1 is ready to install on any mil-spec AR lower.
Like all versions of the M4E1, this one uses a mid-length gas system instead of the shorter, carbine-length system. This allows for smoother, more reliable cycling, which is essential in any match rifle.
Pros:
- Great for competitive shooting
- Relatively easy installation
- Smooth, reliable cycling
- Lifetime manufacturer’s warranty
Cons:
- Does not include bolt/carrier group and charging handle
- Not compatible with 5.56mm NATO rounds
This upper receiver is made with competitive shooters in mind.
5. Stag Arms 15L
The Stag Arms 15L features a 16 ½-inch handguard for plenty of support.
Key features:
- Complete AR upper and barrel
- Flat top design with extended Picatinny rail and handguards
- Fits mil-spec lower receivers
- 5.56mm chamber
- 18-inch barrel with flash suppressor
- Mid-length gas system
- Left-handed design
The Stag Arms 15L ships as a complete upper receiver, with all moving parts installed. It’s chambered in 5.56mm NATO, and is compatible with standard .223 cartridges as well. This upper mounts on a standard, mil-spec AR lower.
The 15L features an 18-inch stainless steel barrel and a matte black flash suppressor. The extended handguard measures 16 ½ inches, which accommodates a variety of stances, and allows you to hold the barrel close to the muzzle for maximum support. A full length Picatinny rail runs from the back of the receiver to the end of the handguard.
The 15L’s mid-length gas system ensures smooth, jam-free operation. It’s durably constructed, although it’s also fairly heavy, at 7.1 pounds. Most importantly, this is a left-handed receiver. If you’re a southpaw, you won’t find a better receiver that’s designed for you.
Pros:
- Quick, easy installation
- Reliable cycling
- Long handguard
- Designed for left-handed use
- Lifetime manufacturer’s warranty
Cons:
- Heavy
This is the most reliable left-handed receiver on the market.
6. Mega Arms AR-15 KeyMod
The Mega Arms AR-15 KeyMod is a complete unit with a handguard and Picatinny rail.
Key features:
- Complete AR upper
- 8 ¾-inch KeyMod handguard with full-length Picatinny rail
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- Includes barrel nut and wrench
The Mega Arms AR-15 KeyMod, like most AR receiver upgrades, is chambered in 5.56mm NATO. This means it has enough strength for high-pressure military rounds, but is still appropriately sized for a civilian .223 cartridge. It’s designed to mount on a standard mil-spec lower receiver.
This receiver requires some assembly. It includes the ejection port door and forward assist button, but not the bolt/carrier group or the charging handle. It also doesn’t include a barrel, which is both a blessing and a curse. On the one hand, you can select your own barrel. On the other hand, barrels are a pain to install.
The KeyMod is named for its KeyMod handguard, which features a full-length Picatinny rail. When assembled, the rail will run continuously from the back of the receiver to the end of the 8 ¾-inch handguard.
Pros:
- Quality KeyMod rail
- Handguard supports a low-profile gas block
- Choose your own barrel
- Lifetime manufacturer’s warranty
Cons:
- Assembly required
- Does not include barrel, bolt/carrier group, or charging handle
This is a versatile upper receiver with a quality KeyMod handguard.
7. Radical Firearms HBAR Radical
The Radical Firearms HBAR Radical features a 16-inch KeyMod handguard with a full-length Picatinny rail.
Key features:
- Complete AR upper and barrel
- Flat top design with Picatinny rail
- Fits mil-spec lower receivers
- 7.62mm NATO chamber
- 18-inch barrel with flash suppressor
The Radical Firearms HBAR Radical is chambered for 7.62mm NATO cartridges, which pack more punch than a 5.56mm NATO round. This gives you plenty of stopping power for a self defense weapon, but comes at the cost of increased recoil and less readily-available ammo.
This receiver comes assembled and ready to mount on a mil-spec lower receiver. However, you’ll need to provide your own bolt/carrier group and charging handle. If you’re upgrading a 5.56mm NATO or .223 caliber AR, don’t re-use your old bolt. You’ll need a bolt that’s designed for the 7.62mm NATO instead.
The HBAR Radical features an 18-inch chrome-moly steel barrel, with a flash suppressor pre-attached. It also includes a 16-inch KeyMod handguard, with a full-length Picatinny rail.
Pros:
- More powerful than .223 caliber or 5.56mm NATO
- Relatively easy installation
- Lifetime manufacturer’s warranty
Cons:
- Does not include bolt/carrier group or charging handle
This upper receiver gives you more stopping power than a standard 5.56mm NATO rifle.
8. Sabre Defence AR-15 Forged Stripped
The Sabre Defence AR-15 Forged is a sturdy receiver that can take a serious beating.
Key features:
- Stripped AR upper
- Flat top design with Picatinny rail
- Fits mil-spec lower receivers
- .223 Remington chamber
The Sabre Defence AR-15 is forged, not billeted from an aluminum block. This makes it significantly more durable than a stock, billeted receiver. It’s chambered for .223 Remington, which means it’s suitable for civilian .223 rounds, but not capable of withstanding the pressure of a 5.56 NATO military round.
This is a stripped receiver, which means it doesn’t come with a barrel or any moving parts. It’s a flat-top design, with a chamber and a Picatinny rail.
You’ll need to install all of the hardware yourself, including the bolt/carrier group, the charging handle, the forward assist button, and the ejection port door. Needless to say, make sure you have all the tools and expertise, or consult a gunsmith if you need assistance.
Pros:
- Can be paired with a variety of hardware and barrels
- Durable, forged construction
- Affordable
Cons:
- Rifle style feed ramps
- Requires significant assembly
This receiver is more durable than a standard, mil-spec receiver.
9. American Spirit Arms Side Charging
The American Spirit Arms Side Charging allows you to chamber a round without losing sight of your target.
Key features:
- Stripped AR upper
- Flat top design with Picatinny rail
- Fits mil-spec lower receivers
- Compatible with .223 Remington, 5.56mm NATO, 7.62mm NATO, or 6.5 Grendel
- Side charging handle
The American Spirit Arms Side Charging is compatible with just about any caliber that can be fired from the AR-15 platform. This includes your standard 5.56mm NATO, .223 caliber, 7.62mm NATO, 6.5 Grendel, and 6.8mm Special.
Like the last receiver we looked at, this is a stripped model, so you’ll need to provide your own hardware and assembly. Be careful about the bolt carrier in particular. This receiver requires a special notch cut in the side. American Spirit Arms will mill the bolt carrier for a fee, or you can buy your own compatible part.
The reason for this notch is the American Spirit Arms’ charging handle, which is located on the side of the gun instead of the back. This allows you to chamber a round without changing your position and losing your sight picture.
Pros:
- Compatible with almost any AR hardware
- Fits several calibers
- Maintain sight picture while chambering a round
Cons:
- Requires a proprietary bolt carrier notch
- Significant assembly required
- Expensive
This receiver is one of the most versatile models available.
10. Bravo Company Flattop
The Bravo Company Flattop is built to fit a variety of calibers.
Key features:
- Complete AR upper
- Flat top design with Picatinny rail
- Fits mil-spec lower receivers
- Compatible with .223 caliber, 5.56mm NATO, 7.62mm NATO, and .300 Blackout
The Bravo Company Flattop is engineered to support almost any caliber that’s compatible with the AR-15. You can use a standard 5.56mm NATO/.223 barrel to use the most readily-available ammo, or attach a 7.62mm, .300, or 6.5 barrel for more stopping power.
This is what’s called a “complete” AR upper, which means it includes the ejection port door and forward assist button. However, you’ll still need to provide your own bolt/carrier group and charging handle.
The Bravo Company AR upper has vice-tight threading on the barrel extension to maximize stability and eliminate the potential for wiggle. If your barrel won’t thread, the manufacturer recommends warming the barrel extension with a hair dryer to get it to expand.
Pros:
- Fits several calibers
- Compatible with almost any AR hardware
- Tight barrel fit
Cons:
- Significant assembly required
- Does not include bolt/carrier group or charging handle
This is a solid upgrade that will improve your accuracy over a stock upper receiver.
11. Bushmaster M4 A2
The Bushmaster M4 A2 is nearly identical to the original M16 upper.
Key features:
- Complete AR upper and barrel
- Carry handle design
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 11 ½-inch barrel with flash suppressor
The Bushmaster M4 A2 is pre-assembled, including the barrel, handguard, bolt/carrier group and charging handle. Just drop it into your mil-spec lower receiver, insert the retention pins, and you’re ready to go out shooting.
We chose this kit because it features a classic, M16-style design on an 11 ½-inch SBR barrel. This includes a bayonet mount near the muzzle, which is sure to make you smile if you’re a fan of authentic military gear. It also features the iconic carry handle rear sight, tall front sight, and comfortable polymer grip that make the M16 so recognizable.
Like any barrel under 16 inches, you’ll need NFA authorization to actually mount the Bushmaster M4 A2 on a rifle. Talk to your local gun dealer about submitting paperwork to register an SBR. Alternatively, you can attach a pistol grip only, and you’ll have a legal AR pistol.
Pros:
- Quick, easy installation
- Comfortable polymer handguard
- Built-in M16-style bayonet mount
Cons:
- Requires SBR registration for rifle use
This receiver converts your AR-15 into an M16-style SBR.
12. Bear Creek Arsenal 10.5″
The Bear Creek Arsenal 10.5” includes one of the most accurate sub-16-inch barrels on the market.
Key features:
- Complete AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 10 ½-inch barrel with flash suppressor
The Bear Creek Arsenal 10.5” is chambered for a standard, 5.56mm NATO round, and also accepts civilian .223 cartridges without any issues. It arrives pre-assembled, including the bolt/carrier group and the charging handle, and mounts quickly and effortlessly on a mil-spec AR frame.
This assembly includes a 9-inch Magpul handguard, with a Picatinny rail that runs the full length of the gun. The barrel itself is forged from chrome-moly steel, and features a chrome lining for corrosion resistance. It also features an impressive 1:7 twist, which gives you tighter bullet rotation and better accuracy than most ARs.
To use this receiver and barrel on a rifle, you’ll need an NFA authorization. Make sure to register your rifle as an SBR to avoid any legal issues. You can also use this barrel with a pistol grip only to build an AR pistol.
Pros:
- Quick, easy installation
- Tight, 1:7 barrel twist
Cons:
- Requires SBR registration for rifle use
This receiver comes with an SBR barrel and Picatinny rail.
13. Aero Precision 10.5″ M4E1
The Aero Precision 10.5” M4E1 features a carbine-length gas system for smoother cycling.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 10 ½-inch barrel with flash suppressor
- Carbine-length gas system
- M16-style front sight
The Aero Precision 10.5” M4E1 is a pre-assembled upper assembly that comes complete with a barrel and a handguard. It’s chambered in 5.56mm, and also accepts .223 caliber cartridges. It requires a bolt/carrier group and a charging handle, but is otherwise ready to mount on your mil-spec lower.
This receiver comes with a 10 ½-inch barrel, so you’ll need to build it into an AR pistol or fill out NFA paperwork for an SBR registration in order to comply with the law. The handguard is 9 inches long, extending right up to the M16-style front sight, which is perfect for co-witness with a red dot sight.
Like the other M4E1 assemblies we’ve looked at, this one features a long gas system. Instead of using a pistol-length gas system, this assembly’s is carbine-length, which allows an extra millisecond for the action to cycle more smoothly.
Pros:
- Quick, easy installation
- Great choice for red dot co-witness
- Smooth, reliable action
Cons:
- Requires SBR registration for rifle use
- Does not include bolt/carrier group or charging handle
This well-engineered upper assembly is extremely reliable.
14. Bravo Company 11.5″ Carbine
The Bravo Company 11.5″ Carbine features a durable, corrosion-resistant manganese phosphate finish.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 11 ½-inch barrel with flash suppressor
- Carbine-length gas system
The Bravo Company 11.5″ Carbine, like most AR-15 uppers, is chambered for the 5.56mm NATO cartridge, and will also fire civilian .223 cartridges. It includes a barrel, rail, and handguard, and only requires a bolt/carrier group and charging handle to be fully operational. Drop it into any mil-spec AR lower, and you’ve got a functioning rifle.
The 10-inch handguard on this assembly extends almost all the way to the end of the barrel, and features a Picatinny rail that runs the full length of the gun. Underneath, you’ll find a carbine-length gas system, which provides smoother, more reliable cycling than a pistol-length system.
As with any barrel under 16 inches, there are a couple of ways you can work with this one. The easiest way is to mount it on an AR lower with a pistol grip and no buttstock. If you want to use it to build an SBR, make sure to do your NFA paperwork to stay on the right side of the law.
Pros:
- Relatively easy installation
- Smooth, reliable action
- Durable finish
Cons:
- Does not include bolt/carrier group or charging handle
- Requires SBR registration for rifle use
This assembly is exceptionally smooth-cycling and jam-free.
15. Daniel Defense MK18
The Daniel Defense MK18 features a long, 10-inch handguard on a 10.3-inch barrel.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 5.56mm NATO chamber
- 10.3-inch barrel with flash suppressor
The Daniel Defense MK18 is chambered in 5.56mm NATO, and also accommodates civilian .223 rounds. It arrives already assembled, and requires only a bolt/carrier group and a charging handle before installation on a mil-spec AR frame.
We included this receiver on our list primarily due to its tight, 1:7 barrel twist. This provides faster bullet rotation, improving your accuracy from a short barrel. The MK18 also includes a 10-inch handguard with a Picatinny rail.
The barrel on the MK18 is only 10.3 inches long. You’ll need to build it into an AR pistol, or get NFA authorization for an SBR if you want to build a rifle.
Pros:
- Relatively easy installation
- Tight, 1:7 barrel twist
Cons:
- Does not include bolt/carrier group or charging handle
- Requires SBR registration for rifle use
If you want your AR pistol or SBR to be as accurate as possible, the MK18 is a solid choice.
16. Aero Precision M4E1 – .300 Blackout
The Aero Precision M4E1 for .300 Blackout is available with barrels in rifle and pistol lengths.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- .300 Blackout chamber
- 8, 10, or 16-inch barrel with flash suppressor
The Aero Precision M4E1 for .300 Blackout is, not surprisingly, chambered for the .300 blackout. This round offers higher stopping power than the standard .223 or 5.56mm NATO, at the expense of reduced accuracy. With this kind of performance, you’re looking at a top-tier short range gun, perfect for home defense.
This assembly is available with three different barrels: 8, 10, and 16 inches. For the 8 or the 10-inch, you’ll need to either build an AR pistol or get NFA authorization to build an SBR. For the 16-inch, it’s business as usual.
Pros:
- Plenty of stopping power
- Multiple barrel lengths available
- Lifetime manufacturer’s warranty
Cons:
- Expensive ammunition
- Does not include bolt/carrier group or charging handle
This offers more stopping power than a standard 5.56mm NATO upper.
17. Bear Creek Arsenal 16″ .300 Blackout
The Bear Creek Arsenal 16″ .300 Blackout is built for stopping power and accuracy.
Key features:
- Complete AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- .300 Blackout chamber
- 16-inch barrel with flash suppressor
Bear Creek Arsenal 16″ .300 Blackout is chambered in .300 Blackout. While this is typically considered a home defense round, Bear Creek includes a barrel with a tight, 1:7 twist that makes the Blackout pinpoint accurate at 100-200 yards. This doesn’t make your AR into a sniper rifle, but it’s more than enough power and accuracy to drop a prize buck.
This assembly includes a 15-inch handguard, which allows you to grip the barrel almost all the way down to the muzzle. It also has a Picatinny rail that extends the full length of your rifle, with plenty of space for your favorite scope or other accessories.
Pros:
- Tight, 1:7 twist
- Plenty of stopping power
- Lifetime manufacturer’s warranty
Cons:
- Relatively heavy
This upper assembly provides exceptional accuracy for .300 Blackout.
18. Aero Precision M5E1 – 6.5 Creedmoor
The Aero Precision M5E1 in 6.5 Creedmoor turns your AR-15 into a hunting rifle.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 6.5 Creedmoor chamber
- 18, 20, or 22-inch barrel with flash suppressor
- Mid-length or rifle-length gas system
The Aero Precision M5E1 in 6.5 Creedmoor converts your AR into a high-powered hunting rifle. If it’s not obvious from the name, this receiver is chambered in 6.5 Creedmoor, possibly the best long-range cartridge on the market. The barrel on this assembly is appropriate for hunting use; it’s available in 18, 20, and 22-inch lengths.
This assembly includes a handguard that’s only 2 inches shorter than the barrel, which features a full-length Picatinny rail. The 18-inch version comes with a mid-length gas system, and the 20 and 22-inch variants come with a rifle-length gas system, providing smooth, jam-free action.
Pros:
- Good for stopping power and long-range accuracy
- Smooth, reliable action
- Lifetime manufacturer’s warranty
Cons:
- Does not include bolt/carrier group or charging handle
If you want to use your AR-15 for long-range shooting, this upper is a strong choice.
19. Critical Capabilities 16″ 9mm
The Critical Capabilities 16″ 9mm is one of the best on the market.
Key features:
- AR upper and barrel
- Flat top design with extended Picatinny rail handguard
- Fits mil-spec lower receivers
- 9mm chamber
- 15-inch barrel with flash suppressor
The Critical Capabilities 16″ 9mm is chambered in 9mm, as the name implies. This makes it poorly suited for hunting or target shooting, but an excellent choice for self defense or home defense. Urban users will appreciate the 9mm even more, because it doesn’t carry or penetrate as far as a .223.
This assembly has low recoil, thanks to the 9mm cartridge. Install a bolt/carrier group and a charging handle, and you’re good to install it in any mil-spec lower receiver. Make sure your hammer and magazine are compatible with 9mm rounds, and you’re ready to go.
Pros:
- Good choice for home defense
- Low recoil
Cons:
- Does not include bolt/carrier group or charging handle
This upper receiver is a good choice for home defense.
20. Rock River Arms A4 9mm
The Rock River Arms A4 9mm includes a comfortable, M16-style polymer handguard and a tall front sight.
Key features:
- Complete AR upper and barrel
- Flat top design with Picatinny rail
- Fits mil-spec lower receivers
- 9mm chamber
- 16-inch barrel with flash suppressor
- M16-style handguard and front sight
The Rock River Arms A4 9mm is designed for home defense and self defense. The 9mm round is powerful enough to stop a home intruder in his tracks, while presenting a minimal danger to your neighbors.
This is a complete assembly, and drops right into any mil-spec lower. It includes an M16-style sight at the end of the 16-inch barrel, which allows for easy co-witness with most red dot sights.
While the A4 9mm is expensive, it’s well worth the price. It allows you to reliably protect your home, while responsibly avoiding high-powered rifle rounds that can travel for thousands of yards.
Pros:
- Quick, easy installation
- Good co-witness for red dot sights
- Low recoil
- Good choice for home defense
Cons:
- Expensive
This upper receiver is ideal for home defense use.
Bottom Line
Whether you’re looking for the best AR complete upper, the best AR pistol upper, or a simple stripped upper to upgrade your rifle, we like to think we’ve presented a wide enough selection to find the best AR upper for your needs.
One thing we should emphasize is that a stripped upper is typically just a housing. So make sure to hang on to your forward assist button, ejection port door, bolt carrier group, and other internal components from your original receiver.
On the same token, a stripped upper can lighten your AR and improve its durability, but won’t change its performance, since you’ll be working with the same moving parts.
On the other hand, a complete upper includes all the moving parts, and generally a barrel and/or a rail system. These kits are more expensive, but offer significantly more options.
And that about covers it. We hope you found the best AR upper receiver to upgrade your rifle.
Check out all the other AR-15 articles put together by our expert team here at Guns & Safety Reviews;
The Review
Best AR-15 Uppers
Check out our review of the best AR-15 uppers on the market today.
Review Breakdown
-
DPMS Oracle
-
Aero Precision M4E1
-
Yankee Hill Machine Black Diamond Specter
-
Aero Precision M4E1
-
Stag Arms 15L
-
Mega Arms AR-15
-
Radical Firearms HBAR
-
Sabre Defence
-
American Spirit Arms Side
-
Bravo Company Flattop
-
Bushmaster M4 A2
-
Bear Creek Arsenal
-
Aero Precision
-
Bravo Company
-
Daniel Defense MK18
-
Aero Precision M4E1
-
Bear Creek Arsenal
-
Aero Precision M5E1
-
Critical Capabilities
-
Rock River Arms
Best AR-15 Uppers DEALS
We collect information from many stores for best price available
