16″ .338 ARC Heavy Barrel – 1:8 Twist, Carbine Gas, Black Nitride
Built around the increasingly versatile .338 Advanced Rifle Cartridge (.338 ARC), this 16-inch heavy-profile barrel combines a 1:8 twist rate, carbine-length gas system and black nitride finish for AR-platform .338 ARC applications.
The .338 ARC brings .338-caliber capability to the AR-15 platform while supporting both supersonic and subsonic ammunition. For hunters, the availability of purpose-designed supersonic hunting ammunition makes the cartridge particularly interesting for short- to moderate-range hunting applications where larger-diameter bullets and substantial terminal performance are priorities. It is back by a limited manufacturer’s warranty against defects.
16″ .338 ARC Barrel Specifications
- Caliber: .338 ARC / .338 Advanced Rifle Cartridge
- Barrel Length: 16″
- Twist Rate: 1:8
- Barrel Material: 4150 Chrome Moly Steel
- Finish: Black Nitride
- Barrel Profile: Smooth / HBAR
- Gas System Length: Carbine
- Gas Block Journal: .750″
- Feed Ramps: M4
- Muzzle Thread: 5/8×24
- Country of Manufacture: USA
U.S.-Made 4150 Chrome Moly Construction
Manufactured in the United States from 4150 chrome moly steel, this .338 ARC barrel is built to provide the strength and durability expected from a quality AR-platform barrel.
The Black Nitride finish provides a durable, low-glare surface with enhanced wear and corrosion resistance.
Carbine-Length Gas System
This barrel is configured with a carbine-length gas system.
Gas-system configuration affects the timing and operation of a direct-impingement AR, particularly when a cartridge may be used with ammunition having substantially different projectile weights and operating characteristics.
Gas-system performance also depends on the complete firearm configuration, including ammunition, gas-port dimensions, gas block, bolt carrier group, buffer system and other components.
5/8-24 Muzzle Threads
The muzzle is threaded 5/8-24, the common muzzle-thread specification used with many .30-caliber muzzle devices. Always verify the thread specification, caliber compatibility, and manufacturer requirements of any muzzle device before installation.
Frequently Asked Questions
What Is .338 ARC?
The .338 Advanced Rifle Cartridge, commonly called .338 ARC, is a .338-caliber cartridge designed to operate within the AR-15 platform as well as compatible micro-action bolt rifles.
One of the defining characteristics of .338 ARC is its ability to support a broad range of projectile weights and both supersonic and subsonic ammunition. That gives the caliber a different performance role from smaller-bore AR cartridges designed primarily around velocity and flatter trajectories.
Rather than trying to make the AR-15 behave like a traditional high-velocity long-action hunting rifle, .338 ARC provides another option for shooters who prioritize heavier, larger-diameter projectiles from a compact AR-platform cartridge.
Why Choose a 16″ .338 ARC Barrel?
A 16-inch barrel is particularly relevant to .338 ARC because the cartridge’s SAAMI velocity and pressure test specifications use a 16-inch test barrel with a 1:8 right-hand twist.
This barrel matches that standardized barrel length and twist rate while providing a full 16-inch barrel configuration for shooters who don’t specifically need a shorter barrel.
The heavy barrel profile adds barrel mass compared with lighter profiles, while the black nitride finish provides a durable treated surface and a clean black exterior.
Is .338 ARC Good for Hunting?
The .338 ARC can be a capable hunting cartridge when paired with ammunition appropriate for the animal being pursued and the expected distance.
Current ammunition options include purpose-designed expanding supersonic bullets, giving hunters choices beyond the heavy subsonic loads for which the caliber initially attracted considerable attention.
The caliber’s larger .338-inch projectile diameter and availability of heavier bullets make it particularly interesting for hunters whose priorities lean toward terminal performance rather than simply achieving the flattest possible trajectory.
As with any hunting cartridge, however, caliber alone does not determine suitability.
Bullet construction, impact velocity, shot placement, distance and the size of the game all matter. Hunters should select ammunition specifically designed for their intended game and remain within the ammunition manufacturer’s recommended performance parameters.
Supersonic and Subsonic .338 ARC
One of the distinguishing characteristics of .338 ARC is the availability of ammunition at both ends of the velocity spectrum.
Supersonic .338 ARC ammunition uses lighter projectiles at higher velocities and is generally the more relevant side of the cartridge for hunting when trajectory and retained velocity matter.
Subsonic .338 ARC ammunition uses substantially heavier projectiles while keeping velocity below the speed of sound. This is one of the applications around which the cartridge was specifically developed.
Hornady has stated that its 307-grain .338 ARC subsonic load produces approximately 1.5 times the energy of its .300 Blackout subsonic offering, illustrating one of the reasons the cartridge has generated interest among shooters looking for greater subsonic performance from the AR-15 platform.
The two types of ammunition serve different purposes, so ammunition should be selected according to the intended application rather than treating all .338 ARC loads as interchangeable in performance.
Who Should Consider .338 ARC?
A .338 ARC barrel may make sense for an AR owner looking for something different from the traditional small-bore AR cartridge.
It is particularly worth considering for shooters interested in:
- A .338-caliber cartridge that fits the AR-15 platform
- Hunting with appropriate supersonic expanding ammunition
- Heavy-projectile capability
- Subsonic ammunition performance
- A cartridge with both supersonic and subsonic ammunition options
- Building a specialized AR rather than another general-purpose 5.56 or .300 Blackout configuration
The best choice ultimately depends on what you expect the rifle to do.
What does .338 ARC stand for?
.338 ARC stands for .338 Advanced Rifle Cartridge. The cartridge was introduced by Hornady and has been standardized by SAAMI.
Does .338 ARC fit the AR-15 platform?
Yes. .338 ARC was designed to operate within the AR-15 platform. Building or converting an AR to .338 ARC requires compatible components; a .338 ARC barrel alone does not make an existing AR compatible with the cartridge.
Is .338 ARC a hunting caliber?
Yes, .338 ARC can be used for hunting with properly selected hunting ammunition. Current factory ammunition includes expanding supersonic loads designed for hunting applications. Game suitability and practical range depend on the particular load, bullet construction, impact velocity and applicable hunting regulations.
Is .338 ARC only a subsonic cartridge?
No. Although subsonic performance is an important part of the .338 ARC concept, factory ammunition is available in both supersonic and subsonic configurations.
Before Building a .338 ARC Upper
Because .338 ARC is not simply a barrel swap for every existing AR configuration, verify the compatibility of the barrel, bolt, magazines, gas-system components and ammunition before completing a build.
Component requirements can vary by manufacturer. Always confirm the specifications of the individual components being used rather than assuming compatibility based solely on the AR-15 platform designation.
Does the barrel include a warranty?
Yes. The barrel is covered by a limited manufacturer’s warranty against defects
Important Compatibility & Legal Notice
Always verify component compatibility and proper installation before use. Barrel length and firearm configuration can affect how a firearm is classified under federal, state, and local law. The purchaser is responsible for ensuring that the completed firearm and its configuration comply with all applicable laws and regulations.
