Sons of Liberty Gun Works AR-15 Rails: A Review

Up until the last few decades, it seemed AR-15 manufacturers were a select few. At the time, the passionate gun owner could probably name all of them offhand with a little practice. As the AR-15’s popularity grew, so did the number of manufacturers. Accordingly, a slew of options for the end user turned the industry on its head. Today, there’s a confusing number of companies producing parts and rifles for the consumer. Some of these companies, like Sons of Liberty Gun Works, have developed a stout reputation for producing quality rifles and components for the AR-15. While there’s a variety within Sons of Liberty Gun Works products, their rails require some special attention to understand what makes them different and why you should consider one for your next AR build.

Sons of Liberty Gun Works

Established around ten years ago, Sons of Liberty Gun Works proudly produces American-made AR-15s and accessories based out of San Antonio, Texas. The company touts absolute transparency in their products. From torque specs to gas port sizing, they’re more than happy to tell you every detail that makes their products stand out.

For many, they hear there’s another manufacturer of AR’s and roll their eyes. Hype and appearance surround the reputation of many companies. For Sons of Liberty Gun Works, anyone who has handled or used one of their rifles or products can attest to the inherent quality embodying everything they produce.

My Experience

Any review worth its salt should have some personal experience woven in. Admittedly, I don’t own a bunch of Sons of Liberty Gun Works products. However, while working for several gunsmiths over the years, I’ve had the opportunity to handle, shoot, and get into the guts of many of their rifles. The quality, fit, and materials are impressive. These guns run — and they run well.

I currently own an “older” production rail from Sons of Liberty Gun Works, the EXO2. The EXO3, which I’ll cover later, has since replaced this rail. While assembling an AR from some parts I’d pieced together, I came across an old EXO2 rail discounted to make way for the EXO3 series. After seeing the quality from Sons of Liberty, it was a no-brainer to pick it up.

Sons of liberty gun works Exo 2 rail on rifle
The older EXO2 rail from Sons of Liberty Gun Works has proven a favorite amongst my rifles, with no issues after 1,000 rounds. [Photo: Tom Stilson]
Since taking ownership of that EXO2, its quality and durability have been impressive. EXO rails are Sons of Liberty Gun Works’ “economy” line. Don’t be fooled; economical doesn’t mean cheap. This rail has performed exceptionally well over the course of the last two years during multiple range outings. While dedicated to a “range queen” rifle, I have no qualms deploying this setup as a patrol or home defense rifle.

Sons of Liberty Gun Works Rails

The company currently offers three rail systems: the EXO3, M89, and M76. These three rails provide different applications, features, and options to the end user depending on their needs and wants. Let’s delve into the features and functions of each.


The EXO3 is a continuation of the Sons of Liberty Gun Works EXO rail line. The EXO3 integrates a longer steel barrel nut which they advertise as an improvement over the original aluminum barrel nut of the EXO2 rail system. The steel barrel nut produces a stiffer surface for the rail when mounted to the barrel nut, improving rigidity and reducing unintended flexion. While I’ve yet to experience any issues with my EXO2, the EXO3’s upgrade is arguably an improvement that only elevates the rail’s quality further.

The new, improved EXO3 rail is built rugged but with the budget-conscious consumer in mind. [Photo: SOLGW]
The EXO3 rail is an economical rail option for the end user that doesn’t require copious amounts of mounting area while mitigating point-of-impact/point-of-aim drift on laser aiming devices for night vision or thermal applications.

Installation is straightforward and includes a barrel nut and tool for installation. Their instructions include the necessary details for proper torque spec during install. Two torque screws secure the rail to the barrel nut (that I haven’t had to adjust over the course of 1,000 rounds). A full-length Picatinny rail tops the EXO3 with M-LOK mounting surfaces at the 3, 6, and 9 o’clock positions. The EXO3’s cost savings partly come from its minimalist M-LOK slots. Despite fewer than its M76 and M89 counterparts, there are plenty of mounting options for a vertical forend, light, and (if desired) bipod attachments.

Currently, GunMagWarehouse offers the EXO3 rail in 9.5” for $180.99, 10.5” for $185.99, 13” for $185.99, and 15” for $194.99. These rails are exceptionally well-made at a competitive price.


The M76 line from Sons of Liberty Gun Works is the foundation of the company’s rail systems. The M76 is a slim, low-profile rail with virtually non-existent point-of-aim to point-of-impact shift when outfitted with an aiming device. While arguably not as critical to the average homeowner looking for a rail to attach their light, this system has proven reliable amongst top-tier end users where those laser systems required absolute rigidity.

The durable Wedge Lock M76 15″ rail from Sons of Liberty Gun Works. [Photo: SOLGW]
The M76 rail features seven mounting planes for M-LOK accessories and an exceptionally sleek profile. It wears a full-length Picatinny top rail for a single continuous mounting surface. The proprietary Wedge Lock design provides sturdy contact between the barrel nut and rail.

GunMagWarehouse currently offers the M76 rail in 10.5” for $304.99 and 15” for $327.99. These rails are professional end-user quality and expected to perform reliably in harsh conditions.


To paraphrase Sons of Liberty Gun Works, the M76 rail benches 500 pounds while the M89 benches 505 pounds. Both are extremely stout rails. However, the M89 is even tougher and stronger than the M76 predecessor. The proprietary Drive Lock mounting system is a novel idea from Sons of Liberty. The rail utilizes three screws to mount the rail to the barrel nut. As the screws tighten, they engage the barrel nut, which “drives” the rail tighter against the receiver. Combined with the anti-rotation tabs on the rail’s receiver, it makes for an incredibly tight and rigid mounting system. This mounting system is arguably as strong, if not stronger than the legendary Daniel Defense RIS and KAC rail mounting systems.

The latest-and-greatest from Sons of Liberty: the M89 Drive Lock rail system. [Photo: SOLGW]
The M89’s M-LOK mounting surfaces are similar to those of the M76, except the rail diameter is slightly larger. This design provides a little more room for accessory mounting between the rail and gas block (not that it was necessary). Furthermore, the M89 rail’s increased mass and larger diameter improve heat dissipation.

GunMagWarehouse sells the M89 rail in a dizzying variety of options, including 8” for $289.99, 9.5” for $299.99, 10.5” for $304.99, 11.5” for $308.99, 13” for $308.99, 13.7” for $308.99, and 15” for $313.99. These rails are undeniably premium products built to withstand virtually any imaginable abuse — realistic or otherwise.

Final Points

With the boom of manufacturers flooding the industry, many products have hit the market in a varied range of quality. In the past, I’ve bought AR-15 parts on a budget. Consequently, the results have been profoundly disappointing. As time wore on, those lessons taught me you don’t need to break the bank to get quality. However, sometimes a few extra dollars spent go a long way. For Sons of Liberty Gun Works, they’ve made an impressive effort to produce stout and reliable rails for all facets of users and budgets.

Tom Stilson began his firearms career in 2012 working a gun store counter. He progressed to conducting appraisals for fine and collectible firearms before working as the firearms compliance merchant for a major outdoor retailer. In 2015, he entered public service and began his law enforcement career. Tom has a range of experience working for big and small as well as urban and rural agencies. Among his qualifications, Tom is certified as a firearms instructor, field trainer, and in special weapons and tactics. If not on his backyard range, he spends his time with family or spreading his passion for firearms and law enforcement.

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