Best AR15 Upper Receiver Options – Ranked and Compared [2024]
Buying an upper receiver is one of the more enjoyable purchases you make when building your rifle. The upper is what really sets the stage for what your rifle is and could be. Heck, it might not even be a rifle. It could be a pistol. This article aims to help you choose the best AR15 upper for your intended build.
An upper receiver contains several important pieces and parts. It is literally the other half of your AR that connects to your AR-15 Lower Receiver. And while the upper receiver might not be the foundation of your AR-15 build, it’s of utmost significance when it comes to determining the weapon’s capabilities within the context of its intended use.
To help you make an informed decision, we’ve gathered some of the best AR-15 upper receivers on the market. Then we’ve delved into work and features to provide a guide and reference point as you begin choosing the best upper for your needs.
Note that this is a guide to complete upper receivers. You can add these uppers directly to a complete AR-15 lower and begin shooting almost immediately.
I think most people will be surprised about the various features they should consider when purchasing a AR 15 upper receiver.
What’s the Upper Receiver?
The upper receiver of an AR-15 is the portion of the weapon that contains the barrel, gas system, and other parts vital to the effective function of the firearm, i.e.:
- your barrel
- the gas system,
- handguard
- sighting system(s)
- bolt carrier group
- ejection port, and
- forward assist.
It’s very clearly an important component of your rifle. Unlike the lower receiver, an upper receiver is not a serialized part of the firearm. An upper receiver can be purchased and shipped directly to your home.
Predictably the upper receiver connects to the lower receiver, forming an entire AR 15. Upper receivers come in numerous calibers and various different designs. Upper receivers can be purchased complete or stripped and in various stages in between.
For this article, we’ve gathered the best complete or near-complete AR15 upper receiver options for your consideration. After all, something about the best stripped uppers would be a fairly boring article. Besides, using complete uppers really shows you the wide variety of things you can do with your AR.
Best AR-15 Uppers
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Best AR-15 Uppers
Here is a list of the best AR-15 uppers you can buy:
- Colt Enhanced Patrol Rifle (EPR) Upper
- Geissele Super Duty Upper
- Daniel Defense Mk18 Upper Receiver
- Stag-15 Tactical Upper Left-Handed
- Sons of Liberty Gunworks Patrol SL
- Foxtrot Mike FM-15 Upper
- Aero Precision 20-inch Rifle Upper
Top AR-15 Upper Specifications
Below is a list of our Best AR-15 Uppers. Here we can compare and line up the specs from each product and help you make the best decision possible.
| AR15 Uppers | Lengths | Handguard | Gas System |
|---|---|---|---|
| Colt EPR Upper | 11, 14.5, 16" | M-Lok | Carbine |
| Geissele Super Duty Upper | 16" | MLOK | Geiselle length |
| Daniel Defense Mk18 Upper Receiver | 10.3" | Quadrail | Carbine length |
| Stag-15 Tactical Upper Left-Handed | 16" | M-LOK | Mid-Length |
| Sons of Liberty Gun Works (SOLGW) M4-76 | 11.5, 13.7, and 16" | Polymer M-LOK | Carbine or Mid-Length |
| Foxtrot Mike FM-15 AR15 Upper | 13.9 and 16" | M-LOK | MId-length |
| Aero Precision 20" Rifle Upper | 20" | Plastic | Rifle |
Best AR15 Upper Reviews
You’ve seen our summary list above of our favorite upper receivers for an AR-15, now it’s time to dive into a review of each upper by comparing their specs, speaking about the product, and looking at the pros and cons.
1. Colt EPR Upper
Colt EPR Upper
Classic Colt quality with an M-Lok rail
Colt EPR Upper Specs
- Barrel Lengths 11, 14.5, and 16 inches
- Handguard Type M-Lok
- Gas System Carbine Length
Colt EPR Upper Review
EPR stands for Enhanced Patrol Rifle. It represents Colt’s most advanced upper receiver. The EPR is designed to meet modern-day needs and requirements. The EPR represents an advance on Colt’s classic M4 style design. The EPR ditches the FSB and embraces a modern handguard, as well as modern folding sights. If you need a modern duty upper, the Colt EPR is here for your next patrol rifle or home defense carbine.
Colt produces the EPR in three barrel lengths. This includes your typical 16-inch carbine, a traditional M4 style 14.5 upper, and a shorty 11.5-inch upper. These various barrel lengths allow you to easily make a rifle, SBR, or AR pistol. The uppers are sold in both stripped and complete configurations. Complete models include the BCG, charging handle, and Magpul sights.
Every EPR upper comes with the Centurion, a free-floating M-LOK rail system. This handguard comes in various lengths, with the longest being 13 inches. It offers plenty of space for whatever goodies you might ever need (or just want). The Centurion rails are fairly lightweight, resulting in the Colt EPR being balanced and light.
Colt sticks mostly to the Mil-Spec design, and you get the forward assist, standard charging handle, shell deflector, and all those basics that make this a standard, easy-to-use upper for any build. To me, the main downside is the carbine length gas system on the 16-inch variant. A mid-length could be used on the 16-inch barrel for a little less recoil and less gas to face.
If that’s not a problem for you, and you want dependability that doesn’t break the one-grand mark, then Colt has you covered.
Colt Enhanced Patrol Rifle (EPR) Pros and Cons
- Awesome Rail
- Comes with Iron Sights
- Affordable Quality
- Carbine Gas system on the 16-inch barrel
Colt EPR Upper Gun Deals
- Awesome Rail
- Comes with Iron Sights
- Affordable Quality
- Carbine Gas system on the 16-inch barrel
2. Geissele Super Duty Upper
Geissele Super Duty Upper
High end, accurate, with loads of proprietary Geissele features.
Geissele Super Duty Upper Specs
- Barrel length 16″
- Handguard type M-LOK
- Gas system Geissele Length
Geissele Super Duty Upper Receiver Review
Let’s say money isn’t a problem and you want the best upper receiver; then it’s tough to beat the Geissele Super Duty upper receiver might be the best bet for your hard-earned cash. The Geissele Super Duty upper provides you with some of the best parts and pieces you could have on an upper. This ensures reliability, control, and accuracy, and what else could you want from an upper receiver?
In the accuracy department, we get a 16-inch barrel that’s cold hammer forged with a phosphate finish and a chrome-lined bore. This is designed to be a duty-grade upper receiver, and a chrome-lined bore might take a little away from accuracy, but the rust prevention and durability are worth the trade-off in a duty carbine.
Geissele Super Duty Pros and Cons
- Built to last
- Awesome rail system
- Best bolt carrier group (BCG) out there
- Expensive
Geissele Upper Deals
3. Daniel Defense Mk18 Upper Receiver
Daniel Defense Mk18 Upper Receiver
Daniel Defense’s ever-popular version of the Naval Special Warfare upper receiver.
Daniel Defense Mk18 Upper Specs
- Barrel length 10.3″
- Handguard type Quad Rail
- Gas system Carbine length
Daniel Defense Mk18 Upper Receiver Review
Speaking of rails used by Special Operations Forces, this is the Daniel Defense version of the Mk18 upper receiver. The Mk18 is a famous close-quarter combat upper receiver designed initially for Naval Special Warfare but is a platform that has become quite popular in recent years with special operations around the United States military. Daniel Defense provides the RIS 2 rail to SOCOM for their modern Mk18s.
The Mk18 upper receiver from Daniel Defense comes stock standard like a modern Mk18. This includes a 10.3-inch barrel that DD cold hammer forges. Cold hammer-forged barrels are impressive when it comes time to maximize accuracy and durability. The carbine gas system is about as long as you can go with this short of a barrel, so you are stuck with the over-gassed nature of the gun.
The RIS2 rail is a heavy-duty quad rail that’s extremely durable and offers a ton of space for mounting accessories. Typically with platforms this short, your rail space is limited, but the RIS2 really opens up your options. Daniel Defense includes the Grip and Rip ambidextrous charging handle and the Daniel Defense flash suppressor. It’s fully outfitted and ready with a Mil-Sec BCG.
Add your sights and lower, and you are ready to go.
The Daniel Defense Mk18 series upper receiver is a great option for those looking for a close-quarters firearm for home defense or duty use. It’s a rock-solid platform and has been well-proven over more than twenty years of war.
DD Mk18 Upper Pros and Cons
- Short and compact
- RIS2 Rail maximizes space
- Grip and Rip charging handle is an excellent design
- Front heavy
Daniel Defense Mk18 Deals
4. Stag-15 Tactical Upper Left Handed
Stag-15 Tactical Upper Left Handed
A dedicated, purpose-built left-handed receiver frame with all the features required in a modern rifle.
Stag-15 Tactical Upper Left-Handed
- Barrel length 16″
- Handguard type M-LOK
- Gas system Mid-length
Stag-15 Tactical Upper Left Handed
Stag Arms has long produced high-quality rifles that keep up with modern standards. With this rifle, you get all the fanciness a modern gun demands, On top of that, you get a truly dedicated left-hand receiver. The AR market typically accommodates lefties with ambidextrous controls, but that’s not a comprehensive answer. Happily, Stag Arms greets left-handed shooters with open arms. They build AR-15s for both righties and lefties, but I want to highlight their left-handed options.
The Stag-15 Tactical is their flagship upper and features a left-handed ejection port. This ensures no lefty is left with pieces of brass kicking them in the face. The Stag-15 Tactical upper drops onto a standard lower receiver, but you will need a Stag Arms left-handed BCG, so keep that in mind. If you’ve never seen a left-hand upper receiver, it’s a bit odd, but they work!
The Stag-15 features a 13.5-inch free-floated M-LOK handguard that offers a lightweight but modular option for mounting goodies. The barrel is a standard 16 inches. It is built with 416R stainless steel and uses a government profile.
That might be the only downside to the Stag-15 upper. The “government profile” sucks.
I’ll give Stag credit for the mid-length gas system. It was a smart move to improve longevity and reduce recoil. The Stag-15 upper offers lefties an alternative to the standard and improves ergonomics for left-handed shooters.
Stag-15 Tactical Left-Hand Upper Pros and Cons
- Designed for left-handed shooters
- Mid-length gas system
- Affordable
- Requires a proprietary bolt
- Government profile barrel
Stag-15 Tactical Left-Hand Upper Deals
5. Sons of Liberty Gunworks Patrol SL
Sons of Liberty Gunworks Patrol SL
Designed by SOLGW to strike a middle ground between budget and quality.
Sons of Liberty Gun Works Patrol SL Upper Specs
- Barrel length 11.5, 13.7, and 16 inches
- Handguard type Polymer M-LOK
- Gas system Carbine or mid-length
Sons of Liberty Gun Works Patrol SL Review
One of the hardest parts of building a rifle is balancing a budget with high-quality parts and pieces. Sons of Liberty Gun Works produces extremely high-quality parts and rifles at the usual cost of quality demands. The crew at SOLGW designed the Patrol SL upper to strike a middle ground between budget and quality.
Like any SOLGW product, the Patrol SL made to the strictest QC standards. It might lack some of the fancier parts and pieces of other rifles, but it’s going to be hard to beat at its price point. It’s cheaper than the Colt or Daniel Defense yet offers proven and capable performance. The SOLGW Patrol SL features the perfect-sized gas port, a 4150 chrome moly vanadium barrel, a low-profile gas block, and a QPQ finish.
The upper features a front sight base and includes a rear sight which is one of the reasons why it’s made our list of best AR15 uppers. To make it even more budget-friendly, it’s ready to go right out of the box due to the sights. The handguard isn’t fancy, and the barrel isn’t free-floated, but it will shoot true. The handguard is a Magpul SL polymer handguard that offers M-LOK slots and is lightweight, budget-friendly, and proven.
The SOLGW Patrol SL won’t blow your mind, but it won’t break the bank either. I don’t think it’s possible to find a better combination of high-quality rifle upper at a low price. It’s perfectly suited for the patrol car or for home defense.
SOLGW Patrol SL Lower Pros and Cons
- Affordable
- Multiple barrel options
- Great trigger
- Not free-floated
SOLGW Patrol SL Upper Receiver Deals
6. Foxtrot Mike FM-15 AR15 Upper
Foxtrot Mike FM-15 AR15 Upper
Unconventional and awesome, this Direct Impingement upper receiver ditches the normal buffer system.
Foxtrot Mike FM-15 AR-15 Upper
- Barrel length 13.9 and16 inches
- Handguard type M-LOK
- Gas system Mid-length
Foxtrot Mike FM-15 AR-15 Upper Review
Do you wanna get weird with it? Like, go completely unconventional? Good, because we have the Foxtrot Mike FM-15 Upper Gen 2. This upper defies normal expectations in several ways. With this upper, you can ditch the receiver extension and buffer system. It uses a novel and patent-pending buffer system localized to the upper receiver. At the same time, it’s still a direct impingement gas system. It’s not just an AR-180 dressed up, but a real AR-15 upper.
It comes complete with a wisely utilized mid-length gas system. Foxtrot Mike describes it as a fail-proof mid-length gas system, and The barrel is free-floated and covered with an M-LOK rail system. That rail is monolithic and allows you to mount optics down the length of the rail without a zero issue. The barrel is 4150 chrome moly and comes in either 16 or 13.9 inches.
The patent gas system allows you to use a folding stock and works with a standard lower receiver. It drops on, attaches, and boom, you’re good to go. The standard AR 15 charging handle is gone. Instead, we get a side-charging upper receiver. The charging handle can be repositioned to either side or to an up/down position.
The proprietary nature of the optic makes it a fair bit different, and to some, that will be a turn-off. It’s different, but it’s effective and does work. Purists won’t like it, but the FM-15 innovates and incorporates something a little new into the AR platform.
Foxtrot Mike FM-15 AR-15 Upper Pros and Cons
- No buffer tube required
- Modular side charging handle
- Monolithic upper
- Unfamiliar ergonomics may not appeal to some
Foxtrot Mike FM-15 AR-15 Upper Deals
7. Aero Precision 20-Inch Rifle Upper
Aero Precision 20-Inch Rifle Upper
A classic, high quality upper receiver with a 20 inch barrel and full rifle-length gas system. Aero Precision makes quality stuff.
Aero Precision 20-Inch Rifle Upper Specs
- Barrel length 20″
- Handguard type M-LOK
- Gas system Rifle
Aero Precision 20″ Rifle Upper Receiver Review
I’d be remiss if I didn’t include at least one rifle-length upper receiver. Suppose you’ve never experienced the smoothness of a rifle-length gas system and a 20-inch barrel. I only like to suggest quality uppers, and Aero Precision strikes a great balance between an affordable price point and a high-quality upper receiver. Their rifle-length upper is about as simple as it gets and won’t break the bank.
When I say simple, I mean it. The Aero rifle upper features old-school plastic handguards from the A1 generation of M16 rifles. These are ultra lightweight and work well enough, but they don’t do anything fancy like, you know, mount accessories. The front sight base is present, and Aero even includes an A4 -style carry handle, so you have a rear sight right out of the gate.
Beneath that fairly standard carry handle sits an optic rail in case you want to go back to 2003. With that said, shooting with a carry handle sight is a lot of fun. It’s a bit more of a challenge, but it is satisfying to ring steel at several hundred yards. The Aero rifle upper is dang near laser-accurate.
A rifle-length gas system also makes the weapon a smooth shooter, with very little recoil and muzzle rise. The greater shooting community tends to sleep on an upper with a 20-inch barrel, but they should really give it a spin. The Aero option offers you plenty of old-school cool and can quickly be turned into something a little more modern.
Aero Precision 20-Inch Rifle Upper Pros and Cons
- Supremely accurate
- Light recoil
- Comes with sights
- Lacks modularity out of the box
Aero Precision 20-Inch Rifle Upper Deals
Best AR-15 Uppers – a Buyers Guide
The Upper Decks: Complete to Stripped
When you start shopping for the best AR15 upper receivers, you will come across many various configurations. It’s not always as simple as getting exactly what you want. You may have to pick and choose which parts you want as you construct the upper receiver. In that case, buying a complete upper might be a waste of time and money, so you might purchase a stripped upper. What does all that mean? Well, let’s dive into it.
Upper Receivers
Complete Upper – A complete upper will have everything you need to have a functional upper receiver. This includes the upper, barrel, handguard, all the parts and pieces, the bolt carrier group, and possibly the sights. Sights are typically optional and tend to be an optional part of completion. Given how many AR owners are particular about a preferred sight, that’s not necessarily a bad thing.
Complete Basic – A complete basic upper will have all the basic parts of an upper receiver. This includes the barrel, handguard, and small parts and pieces. What’s missing is the bolt carrier group and charging handle, and likely the sights.
Quasi-Stripped – A quasi-stripped upper typically has the upper, barrel, gas system, and small parts and pieces. They are typically missing the handguard and often the BCG and charging handle. These uppers give you solid construction and allow you to personalize your handguard, charging handle, and BCG choices without needing to install the barrel and gas system.
Stripped – Stripped uppers are literally just the upper receiver. No barrel, gas system, forward assist, or dust cover. You have to do everything to install every part to form a complete upper receiver.
Barrel Length(s)
When building or purchasing an upper, you need to pay special attention to the length of the barrel. We’ve done an entire article on AR 15 barrels, so be sure to check that out for more in-depth information on barrel selection. For this article, let’s address some potential legal considerations.
Any upper receiver with a barrel less than 16 inches cannot be mounted to a lower receiver with a rifle stock without a tax stamp and form approval from the ATF. This becomes a short-barreled rifle and is an NFA-regulated item. You can attach an upper with a shorter barrel, like the suggested Danial Defense Mk18 upper, to an AR lower without a stock in a pistol configuration.
Things can get a little tricky with 14.5-inch barrels. These are the standard for the M4 but would make your rifle an SBR. Some of these uppers feature a 14.5 (or even shorter) barrel with a permanently affixed muzzle device that brings the length to 16 inches. This will not make your rifle an SBR. Permanently affixed means the muzzle device is typically drilled, then a pin is inserted, followed by welding to ensure it cannot be removed.
Handguard Options
Handguards do a lot more than guard your hand these days. Admittedly they do ensure you aren’t gripping a hot barrel. However, the modern handguard also implements either a rail system or a modular attachment system to mount accessories. This allows you to mount your favorite goodies, including lights, lasers, and what you have.
Modern AR-15 handguards are often M-LOK designs that allow you to mount accessories and rails exactly where you want them. Keymod is a similar system but is fairly rare. Quad rail is a term for a handguard that is made up of four rows of Picatinny rails.
Rails vary in length, and the length will be determined by a few things. Barrel length is one. You don’t want the handguard to go over the barrel unless you use a specially designed muzzle device. Also, the presence of a front sight base can also limit your handguard length.
The benefits of a long rail are more room to grab the gun and more room to mount accessories. Certain accessories like lights benefit from being mounted further forward, so this might be a consideration. Shorter handguards are typically lighter in weight and also more affordable.
If you are interested in maximizing accuracy, you might want a free-floated rail. Free-floated rails ensure any pressure put on the handguard is not translated to the barrel. Most modern handguards are free-floated, but users with front-sight bases might have a tougher time finding a free-floated option.
The Wonderful World of Upper Receivers
Upper receivers will help dictate what your rifle will be used for. Maybe it’s a long-range precision rifle, maybe it’s a defensive rifle, or maybe it’s something completely different. It’s not wise to cheap out on anything in your rifle, but this is especially true with the upper receiver of your rifle. Be selective, be picky, and get what you want.
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About Travis Pike
Travis is a former United States Marine Corps Infantryman and currently a firearms writer, instructor, and works in Emergency Management.
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