338 ARC Upper Assemblies ACCURATE + RELIABLE
The 338 ARC (Advanced Rifle Cartridge) is the latest innovation in the AR-15 world, designed to bring heavy-hitting, big-bore performance to the compact and lightweight AR-15 platform. Developed to maximize terminal ballistics at both subsonic and supersonic velocities, a 338 ARC upper allows you to deliver massive energy—comparable to the 8.6 Blackout—without the weight and bulk of an AR-10. Whether you are building a dedicated suppressor-ready "thumper" for discreet operations or a powerful short-range hunting rifle, the .338 ARC offers a unique combination of portability and knockdown power.
Redefine the limits of the AR-15 platform with our selection of 338 ARC uppers. Engineered by Hornady to surpass the 300 Blackout in every metric, the 338 Advanced Rifle Cartridge delivers 1.5x more subsonic energy, making it the premier choice for suppressed hunting and tactical applications. These upper receivers allow you to launch massive 307gr Sub-X projectiles from a lightweight, standard-frame AR-15 without the bulk or weight of a large-frame AR-10. Whether you are targeting feral hogs or looking for a discreet home-defense solution, the 338 ARC provides .44 Magnum-tier lethality with the modularity of the modern sporting rifle.
338 ARC Uppers For Sale
Why Upgrade to a .338 ARC Upper Assembly? Heavy-Hitting Performance & Suppressed Capability
.338 ARC: Big Bore Performance from the AR-15 Platform
The .338 ARC (Advanced Rifle Cartridge) was developed by Hornady to maximize the performance of heavy .338-caliber bullets within the AR-15 platform. By upgrading to a purpose-built .338 ARC Upper Assembly, you gain a rifle capable of delivering exceptional energy, excellent terminal performance, and outstanding suppressed capability without moving to the larger AR-10 platform. Whether shooting heavy subsonic ammunition through a suppressor or supersonic hunting loads, the .338 ARC offers versatility that few AR-15 cartridges can match. Our .338 ARC upper receivers utilize a 6.5 Grendel Type II bolt because the cartridge shares the same case head as the 6.5 Grendel family.
Performance Advantage
Installing a purpose-built .338 ARC upper on your standard AR-15 lower gives you access to one of the newest and most capable heavy-caliber cartridges available today. The .338 ARC was engineered to provide excellent feeding reliability, efficient powder burn in shorter barrels, and impressive terminal performance using both subsonic and supersonic ammunition. Whether your goal is hunting, suppressed shooting, or building a hard-hitting AR-15, the .338 ARC delivers exceptional versatility while maintaining the familiar ergonomics of the AR-15 platform.
Industry Experience
Every AR15Elite.com AR-15 upper is assembled using premium American-made components manufactured to precise AR-15 specifications. Each upper is individually inspected for fit and function and professionally checked for proper headspace using Manson Go and No-Go gauges before shipping to help ensure safety, reliability, and consistent performance. Choose from multiple barrel lengths, handguards, and premium barrel materials to build the ideal .338 ARC upper for your specific application.
Why It Matters
| Feature | Specification | Why It Matters |
|---|---|---|
| Cartridge | .338 ARC (Hornady) | Designed to deliver outstanding terminal performance using both heavy subsonic and powerful supersonic .338-caliber bullets while remaining compatible with the AR-15 platform. |
| Platform | AR-15 | Provides big-bore performance without the size and weight of an AR-10 rifle. |
| Bolt Compatibility | 6.5 Grendel Type II Bolt | The .338 ARC shares the 6.5 Grendel case head, requiring a compatible Type II bolt for proper headspacing and reliable extraction. |
| Magazine Compatibility | 6.5 Grendel AR-15 Magazines | Designed to feed the larger cartridge reliably while maintaining AR-15 compatibility. |
| Typical Barrel Twist | 1:8 Twist | Optimized for stabilizing both heavy subsonic bullets and modern supersonic hunting projectiles. |
| Gas System | Pistol or Carbine Length (Depending on Barrel) | Proper gas system selection helps ensure reliable cycling with both subsonic and supersonic ammunition. |
| Barrel Material | 416R Stainless Steel | Provides excellent corrosion resistance and outstanding accuracy for hunting and precision shooting. |
| Handguard | M-LOK Free-Float | Free-floating the barrel improves accuracy while allowing easy installation of lights, bipods, slings, and other accessories. |
| Muzzle Thread | 5/8x24 TPI | The industry standard for .338-caliber barrels, making it easy to install suppressors, flash hiders, or muzzle brakes. |
| Primary Applications | Suppressed Shooting, Hunting & Recreational Shooting | Delivers exceptional versatility with excellent subsonic performance and powerful supersonic hunting capability from the AR-15 platform. |
.338 ARC Upper FAQs
What is a .338 ARC upper?
A .338 ARC upper is an AR-15 upper receiver chambered for the .338 Advanced Rifle Cartridge (ARC). Developed by Hornady, the cartridge is designed to deliver excellent terminal performance using heavy .338-caliber bullets while remaining compatible with the AR-15 platform.
Does the .338 ARC upper come ready to use?
Yes. Every AR15Elite.com .338 ARC upper is fully assembled, inspected for fit and function, and professionally checked for proper headspace using Manson Go and No-Go gauges before shipping. Review the individual product listing to determine whether a bolt carrier group and charging handle are included.
Will a .338 ARC upper fit my standard AR-15 lower?
Yes. A .338 ARC upper is designed to fit a standard mil-spec AR-15 lower receiver. The upper requires the proper bolt and compatible magazines, but no special lower receiver is needed.
What bolt carrier group does a .338 ARC upper use?
The .338 ARC uses a standard AR-15 bolt carrier with a compatible 6.5 Grendel Type II bolt. Because the cartridge shares the 6.5 Grendel case head, a standard 5.56 NATO bolt is not compatible.
What magazines are used with a .338 ARC upper?
The .338 ARC uses AR-15 magazines designed for the 6.5 Grendel family of cartridges. Quality magazines are important for dependable feeding and reliable operation.
Is the .338 ARC good for suppressed shooting?
Yes. The .338 ARC was engineered with suppressed shooting in mind. It performs exceptionally well with heavy subsonic bullets while also offering capable supersonic performance for hunting and general shooting when paired with appropriate ammunition.
What barrel length is best for a .338 ARC upper?
Barrel lengths between approximately 12.5 and 18 inches are common for the .338 ARC. Shorter barrels create a compact rifle that performs well with suppressors, while longer barrels provide additional velocity for supersonic ammunition.
Is the .338 ARC good for hunting?
Yes. The .338 ARC was developed to provide excellent terminal performance for hunting medium-sized game at practical distances. Proper bullet selection, shot placement, and compliance with local hunting regulations are essential for ethical hunting.
What is the effective range of the .338 ARC?
The effective range depends on barrel length, ammunition, and the intended application. Supersonic loads provide strong performance at moderate hunting distances, while heavy subsonic loads are generally intended for shorter-range use, particularly when paired with a suppressor.
Does the .338 ARC have more recoil than 300 Blackout?
Generally, yes. The .338 ARC typically fires larger and heavier bullets than the 300 Blackout, resulting in increased felt recoil. However, recoil remains very manageable in a properly configured AR-15 and is influenced by the rifle's weight, gas system, buffer system, and muzzle device.
What is the difference between the .338 ARC and 300 Blackout?
Both cartridges perform well in the AR-15 platform and are excellent choices for suppressed shooting. The .338 ARC was designed to deliver increased bullet weight and energy while maintaining reliable performance with both subsonic and supersonic ammunition. The 300 Blackout benefits from broader ammunition availability and widespread component compatibility.
What gas system is best for a .338 ARC upper?
The ideal gas system depends on barrel length and the intended ammunition. Most .338 ARC uppers use carefully tuned gas systems designed to provide reliable function with both subsonic and supersonic loads while minimizing unnecessary recoil.
How long until my .338 ARC upper ships?
Most AR15Elite.com orders ship within one to three business days. During holidays or periods of unusually high demand, shipping may take slightly longer. Tracking information is emailed as soon as your order ships.
Why should I buy a .338 ARC upper from AR15Elite.com?
Every AR15Elite.com upper is assembled using premium American-made components and individually inspected for fit and function. Each upper is professionally checked for proper headspace using Manson Go and No-Go gauges before shipping to help ensure safe, reliable, and consistent performance.