AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly Review

First Impressions of AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly

The AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly is a fascinating piece of engineering, promising to transform any standard AR-15 lower into a 5.7x28mm platform. It’s an intriguing concept, essentially allowing you to swap calibers with a simple upper receiver change. The prospect of having an AR-platform rifle chambered in the same round as the iconic FN P90 piqued my interest.

I’ve always been drawn to multi-caliber weapon systems. The idea of adapting a single lower receiver to various scenarios is appealing. I wanted a versatile platform capable of handling both close-quarters engagements and longer-range target shooting, and the 5.7x28mm round seemed like a good compromise.

Upon unboxing, the AR57 upper receiver presents a robust, almost industrial aesthetic. The monolithic aluminum receiver and the melonite-treated steel components inspire confidence. The M-LOK rail system also hints at modern adaptability.

Compared to dedicated 5.7x28mm rifles like the Ruger 57 or the FN PS90, the AR57 offers a different appeal. It provides the familiar ergonomics of the AR-15. This felt like a potentially superior option because it leveraged my existing AR-15 knowledge and accessory pool.

Initially, I was excited by the potential. The build quality appeared solid, and the concept was undeniably cool. My main concern revolved around reliability; would it live up to its claims of consistent cycling and easy maintenance?

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Real-World Testing: Putting AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly to the Test

First Use Experience

My first outing with the AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly was at an outdoor range. I mounted it onto my trusted AR-15 lower, ensuring a snug fit, and loaded up some FN 5.7x28mm ammunition. The weather was clear and sunny, perfect for sighting in the optic.

The first few rounds were a revelation. The recoil impulse was notably lighter than a standard .223/5.56 AR-15. The unique top-loading, bottom-ejecting system functioned flawlessly, with spent casings cleanly dropping through the magazine well.

The only initial issue was a slight learning curve with magazine changes. The top-mounted magazine requires a different manipulation than the standard AR-15 magazine. But I quickly adapted.

Extended Use & Reliability

After several range sessions totaling over 500 rounds, the AR57 upper receiver has proven remarkably reliable. I have used both FN and American Eagle ammunition. Both performed without any noticeable difference.

The melonite finish has held up extremely well. It shows no signs of wear despite repeated use and cleaning. Cleaning is surprisingly straightforward, thanks to the blowback design and easily accessible bolt.

Compared to my experiences with other AR-15 caliber conversions, the AR57 stands out in its simplicity and reliability. There’s no gas system to fuss with. The straightforward design minimizes potential points of failure.

Breaking Down the Features of AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly

Specifications

• The AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly is chambered in 5.7x28mm. This allows for a flatter trajectory and lower recoil than traditional AR-15 calibers.
• It features a 16-inch lightweight barrel with a 1:8.5 twist rate. This provides a good balance between maneuverability and accuracy.
• The overall length is 18 inches with the included muzzle brake, which is attached via 1/2×28 threads. This allows for easy replacement of the muzzle device.
• The receiver is constructed from a 7075 T6 aluminum monobloc. This offers exceptional strength and rigidity.
• It utilizes an M-LOK rail system for accessory attachment. This provides ample space for optics, lights, and other tactical gear.
• The bolt is made from 8620 alloy steel. This ensures longevity and consistent performance.
• It includes a steel barrel, muzzle brake, bolt carrier group, buffer, and screws, all built into an alloy monobloc receiver. This makes it ready to drop in and push pin onto your existing lower.

The 5.7x28mm caliber provides a unique shooting experience. The lightweight projectile offers reduced recoil and a flatter trajectory, enhancing accuracy at longer ranges. The 7075 T6 aluminum receiver ensures durability and rigidity, while the M-LOK rail system allows for extensive customization.

Performance & Functionality

The AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly performs exceptionally well. It’s accurate, reliable, and easy to use. The top-loading, bottom-ejecting design ensures consistent cycling and minimizes malfunctions.

Its strengths lie in its simplicity and compatibility. It seamlessly integrates with any standard AR-15 lower. The reduced recoil and flat trajectory make it a joy to shoot.

One potential area for improvement is the availability of higher-capacity magazines. While the standard 50-round magazines are adequate, more options would be welcome. It undeniably meets and exceeds expectations, providing a unique and enjoyable shooting experience.

Design & Ergonomics

The build quality is top-notch. The materials used are robust and well-finished. The weight is well-balanced, making it comfortable to handle.

It is reasonably user-friendly, but the top-loading magazine system does require some familiarization. Overall, the design is functional and aesthetically pleasing.

Durability & Maintenance

The AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly is built to last. The melonite-treated steel components and 7075 T6 aluminum receiver offer excellent resistance to wear and tear.

Maintenance is relatively simple. The blowback design minimizes fouling, and the bolt is easily accessible for cleaning. Regular lubrication is essential for optimal performance.

Accessories and Customization Options

The AR57 upper receiver is compatible with a wide range of AR-15 accessories. This includes optics, lights, grips, and stocks. The M-LOK rail system allows for easy attachment of these accessories.

While the AR57 is designed to work with standard AR-15 lowers, some users have reported needing a heavier buffer for optimal cycling. Compatibility with aftermarket triggers and other internal components is generally good, but it’s always wise to test compatibility before making modifications.

Pros and Cons of AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly

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Who Should Buy AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly?

The AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly is perfect for shooters who:

• Want a versatile multi-caliber AR-15 platform.
• Appreciate the low recoil and flat trajectory of the 5.7x28mm round.
• Desire a reliable and easily maintained upper receiver.

Those who should skip this product:

• Those seeking maximum stopping power in a rifle platform.
• Shooters who prefer traditional AR-15 calibers.

Must-have accessories or modifications:

• Quality optic (red dot or scope).
• Reliable 5.7x28mm magazines (FN or ProMag).
• Potentially a heavier buffer for optimal cycling.

Conclusion on AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly

The AR57 ULT 16in Barrel 5.7x28mm Upper Receiver Assembly offers a unique and compelling shooting experience. It delivers on its promise of easy caliber conversion and reliable performance. The value proposition is strong, particularly for those already invested in the AR-15 platform.

I would definitely recommend this product. It’s a fun, accurate, and well-built upper receiver that adds a new dimension to the AR-15 platform. If you’re looking for a versatile and enjoyable shooting experience, give the AR57 a try.