Rock River Arms Mid-Length A4 9MM Luger Upper Review

Field Notes on the Rock River Arms Mid-Length A4 9MM Luger Completed Upper

The AR-9 platform has exploded in popularity, offering a cost-effective and enjoyable alternative to traditional AR-15 rifles. The Rock River Arms Mid-Length A4 9MM Luger Completed Upper promises to deliver reliable performance and accuracy in a readily assembled package. It’s designed for shooters who want a dedicated 9mm AR without the hassle of piecing together components from various manufacturers.

I was looking for a reliable 9mm upper receiver to build a dedicated pistol caliber carbine (PCC) for range use and home defense. I wanted something that was known for its quality and reliability. After extensive research, the Rock River Arms upper seemed to consistently deliver on those fronts.

Out of the box, the upper receiver assembly felt solid and well-constructed. The anodized finish was even and consistent, and the components fit together tightly. The weight felt appropriate for the size, and the overall design looked clean and functional.

I considered other options like the CMMG Radial Delayed Blowback system or a similar upper from Palmetto State Armory, but the Rock River Arms reputation for quality and the simplicity of the blowback system swayed me. I valued reliability and consistency above all else. I wanted something that would run smoothly out of the box, with minimal tinkering required.

My first impression was definitely positive. The build quality and reputation of Rock River Arms gave me confidence that this would be a solid addition to my AR collection. I was eager to get it to the range and see how it performed.

Real-World Testing: Putting Rock River Arms Mid-Length A4 9MM Luger Completed Upper to the Test

First Use Experience

I tested the Rock River Arms Mid-Length A4 9MM Luger Completed Upper at my local indoor shooting range. I paired it with a dedicated 9mm lower receiver that accepted Glock magazines. I used a variety of 9mm ammunition, including 115-grain FMJ, 124-grain FMJ, and 147-grain JHP rounds.

The upper performed flawlessly right from the start. There were no failures to feed, extract, or eject with any of the ammunition types I tested. The mid-length gas system, although not directly relevant to a blowback 9mm, contributed to a balanced feel and reduced felt recoil.

The upper was easy to use and required no adjustments or modifications. After the first few magazines, it was clear that this was a reliable and accurate platform. I was impressed with its consistent performance and smooth operation.

Extended Use & Reliability

After several months of regular use, the Rock River Arms Mid-Length A4 9MM Luger Completed Upper has proven to be incredibly reliable. It has seen hundreds of rounds of various ammunition types and continues to perform flawlessly. I have used it in various scenarios, from casual target shooting to more structured drills and exercises.

The finish has held up well to regular handling and use. There are no noticeable scratches or wear marks. Cleaning and maintenance are straightforward, requiring only basic tools and solvents.

Compared to some of my other AR platform rifles, the Rock River Arms 9mm upper has been remarkably trouble-free. Its reliability and ease of maintenance make it a standout performer. It exceeds my expectations for a blowback 9mm upper receiver.

Breaking Down the Features of Rock River Arms Mid-Length A4 9MM Luger Completed Upper

Specifications

• Caliber: 9mm Luger provides a cost-effective and readily available ammunition choice. Its popularity makes it easy to find a wide variety of loads for different purposes.
• Weight: 5 lbs is a reasonable weight for a 16-inch barreled upper receiver. This weight helps to manage recoil and contributes to overall stability.
• Barrel Length: 16 inches strikes a good balance between maneuverability and ballistic performance. This is also the ideal length for maximizing the potential of the 9mm cartridge.
• Barrel Twist Rate: 1-10 optimizes performance with a wide range of 9mm bullet weights. This twist rate is common and works well with most standard ammunition.
• Threads per Inch: 1/2×36 allows for the use of standard 9mm muzzle devices. This opens up a wide range of customization options, including suppressors.
• Muzzle Device: A2 Flash Hider effectively reduces muzzle flash. The A2 flash hider is a classic and functional design that performs well.
• Finish: Anodized provides a durable and corrosion-resistant finish. The anodized finish helps to protect the aluminum components from wear and tear.
• Barrel Material: Chrome Moly enhances barrel life and accuracy. Chrome Moly steel is a popular choice for barrels due to its durability and heat resistance.
• Handguard Length: 11 inches offers ample space for accessories and a comfortable grip. This length provides enough real estate for various shooting styles.

Performance & Functionality

The Rock River Arms Mid-Length A4 9MM Luger Completed Upper performs exceptionally well in terms of accuracy and reliability. It consistently produces tight groupings at typical pistol ranges. The reliable blowback operation ensures consistent cycling with a variety of ammunition types.

Its strengths lie in its reliability, accuracy, and ease of use. However, the blowback system is inherently dirtier than other operating systems, which can lead to increased cleaning frequency. It surpasses expectations for a simple and dependable 9mm upper receiver.

Design & Ergonomics

The upper receiver is well-built with high-quality materials. It feels solid and durable. The weight is manageable, and the mid-length handguard provides a comfortable grip.

The upper receiver assembly is user-friendly. It requires no special tools or expertise to install and operate. The Rock River Arms upper assembly is simple and intuitive.

Durability & Maintenance

The anodized finish and chrome moly barrel contribute to long-term durability. Proper maintenance, including regular cleaning and lubrication, will ensure a long service life. The upper receiver is easy to maintain and requires no special tools or procedures.

Accessories and Customization Options

The Rock River Arms Mid-Length A4 9MM Luger Completed Upper is compatible with a wide range of AR-15 accessories. It can be easily customized with different optics, sights, and muzzle devices.

The upper receiver accepts standard AR-15 handguards, allowing for even further customization. This compatibility with aftermarket parts enhances its versatility. It is also a very affordable and widely available platform.

Pros and Cons of Rock River Arms Mid-Length A4 9MM Luger Completed Upper

Who Should Buy Rock River Arms Mid-Length A4 9MM Luger Completed Upper?

The Rock River Arms Mid-Length A4 9MM Luger Completed Upper is perfect for:

• Range shooters: Enjoy a cost-effective and enjoyable alternative to traditional AR-15 rifles.
• Home defense enthusiasts: Provides a reliable and accurate platform for personal protection.
• PCC competitors: A solid foundation for building a competitive pistol caliber carbine.

This product might not be ideal for shooters who prioritize:

• The absolute lightest recoil: Other operating systems might offer a softer shooting experience.
• Minimal cleaning: Those looking for the least amount of maintenance might consider a different system.

A must-have accessory is a quality 9mm buffer and spring kit to ensure proper cycling and reliability. A red dot optic can also greatly enhance accuracy and target acquisition speed.

Conclusion on Rock River Arms Mid-Length A4 9MM Luger Completed Upper

The Rock River Arms Mid-Length A4 9MM Luger Completed Upper is a fantastic option for anyone looking to build a reliable and accurate 9mm AR platform. It offers exceptional value for the money, providing performance that rivals more expensive options.

The price is definitely justified considering the quality of construction and the proven reliability of the Rock River Arms brand. It offers a great entry point into the 9mm AR world.

I would absolutely recommend the Rock River Arms Mid-Length A4 9MM Luger Completed Upper to anyone looking for a dependable and enjoyable 9mm AR experience. Its simplicity, reliability, and accuracy make it a standout performer. Grab yours today and experience the fun of the AR-9 platform!