Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk Review

First Impressions of Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk

The Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk promises to be a workhorse for precision shooting and varmint hunting. This barrel assembly combines the renowned Rock River Arms quality with the versatility of the .308 cartridge. The non-threaded barrel is a key feature for those in restrictive states or who prefer a clean, classic look.

I’ve been searching for a barrel upgrade for my AR-10 platform to enhance its long-range capabilities and improve accuracy for prairie dog hunting. My current setup is more geared towards general purpose use, but I need something that can consistently deliver sub-MOA performance. I was specifically looking for a 20-inch barrel in .308 with a varmint profile to achieve optimal ballistics and stability at longer distances.

My first impression was of a solid, well-machined piece of equipment. The weight felt substantial, suggesting a robust construction, and the black finish appeared uniform and durable. The gas block was securely attached, giving me confidence in its reliability.

I considered similar barrel assemblies from Wilson Combat and Criterion Barrels, but the Rock River Arms offering struck a balance between price and reputation. I felt that Rock River Arms provided a proven track record and a level of quality that matched my needs without breaking the bank. I also valued the non-threaded option, simplifying the process for my specific AR-10 build.

Initially, I was excited about the potential accuracy and reliability of this barrel assembly. I was also slightly apprehensive about the non-threaded barrel, worrying about future flexibility regarding muzzle devices. But the overall impression was positive, and I was eager to install it and see how it performed.

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Real-World Testing: Putting Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk to the Test

First Use Experience

I first tested the Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk at my local outdoor shooting range. The weather was clear and sunny with a slight breeze, ideal conditions for sighting in a new barrel. I used a variety of .308 ammunition, ranging from 168-grain match loads to 150-grain hunting rounds, to evaluate its versatility.

The barrel performed admirably in these conditions. It was surprisingly accurate right out of the box, achieving consistent 1-MOA groups with the match ammunition after zeroing. The rifle length gas system seemed to cycle smoothly, minimizing recoil and allowing for quick follow-up shots.

Installation was straightforward, but I did have to slightly adjust the gas block to achieve perfect cycling with all ammo types. There were no significant issues, and the overall experience was positive and encouraging.

Extended Use & Reliability

After several months of regular use, the Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk has proven to be a reliable and accurate performer. I’ve taken it on several prairie dog hunts in dry, dusty conditions, and it has consistently delivered hits at distances out to 600 yards. The barrel has also seen use in some wet conditions, and it has shown no signs of rust or corrosion.

Durability has been excellent; there are no visible signs of wear or tear despite several hundred rounds fired. Cleaning is also relatively easy, thanks to the smooth bore of the chrome moly steel. I typically clean it after each range session or hunting trip, and it has maintained its accuracy and performance.

Compared to my previous experiences with other AR-10 barrels, this Rock River Arms assembly noticeably outperforms them in terms of accuracy and consistency. The varmint profile contributes to greater stability and heat dissipation, making it ideal for extended shooting sessions.

Breaking Down the Features of Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk

Specifications

The Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk is designed for the AR-10 platform. It features a 20-inch barrel chambered in 7.62x51mm NATO (.308 Winchester). The barrel is made from chrome moly steel, offering a good balance of durability and accuracy.

The barrel has a varmint profile, meaning it’s thicker than a standard barrel, providing increased rigidity and heat dissipation. This is essential for maintaining accuracy during extended shooting sessions. The gas system is rifle length, which typically results in smoother cycling and reduced recoil compared to shorter gas systems.

The gas block journal size is .936 inches, a common dimension that allows for compatibility with various aftermarket gas blocks if desired. It features a 1-10 twist rate, ideal for stabilizing a wide range of bullet weights commonly used in .308 ammunition. The barrel is non-threaded, making it compliant in areas with restrictions on threaded barrels.

The entire assembly weighs approximately 55 ounces (3.44 lbs), contributing to the overall weight of the rifle but also enhancing stability. This weight distribution helps in reducing muzzle rise and improving accuracy, particularly in supported shooting positions.

Performance & Functionality

The Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk excels in delivering accuracy and consistent performance. During range testing, it consistently produced sub-MOA groups with match-grade ammunition. The rifle length gas system contributes to smooth cycling and manageable recoil, even with heavier bullets.

Its primary strength lies in its ability to maintain accuracy even after multiple rounds. The varmint barrel profile efficiently dissipates heat, minimizing barrel flex and ensuring consistent point of impact. However, a potential weakness for some is the non-threaded barrel, which limits the options for adding muzzle devices like suppressors or compensators.

Overall, the barrel assembly exceeds expectations, providing a significant upgrade in accuracy and reliability compared to standard AR-10 barrels. It transforms the rifle into a capable precision platform, suitable for both varmint hunting and long-range target shooting.

Design & Ergonomics

The Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk exhibits excellent build quality. The materials used feel robust and the machining is precise. The black finish is even and appears durable, providing protection against corrosion and wear.

While the barrel assembly itself doesn’t directly affect ergonomics, its weight and profile contribute to the overall balance of the rifle. The added weight of the varmint profile can enhance stability in supported shooting positions. There is no learning curve associated with its use.

Durability & Maintenance

Given the chrome moly steel construction, the barrel assembly is expected to last for thousands of rounds with proper care. The chrome moly steel is resistant to wear and corrosion. Routine cleaning is straightforward.

Regular cleaning with a bore brush and solvent is typically sufficient to maintain optimal performance. There are no known inherent maintenance issues associated with this product.

Accessories and Customization Options

The barrel assembly comes with a pre-installed gas block, simplifying the installation process. However, given the .936 gas block journal size, users have the option to replace the gas block with adjustable models for fine-tuning gas regulation. The non-threaded barrel limits muzzle device options.

The barrel assembly is compatible with any AR-10 upper receiver designed for a 20-inch barrel and rifle length gas system. Various optics, bipods, and other accessories can be added to the complete rifle to further enhance its capabilities.

Pros and Cons of Rock River Arms 20in .308 CM Varmint Non Threaded Barrel Assembly w/Gas Blk