CM7S 338 ARC 8″ Barreled Action

CM7S 338 ARC Remage Barreled Action – 8″

The Chattahoochee Munitions 338 ARC Remage Barreled Action combines the CM7S Remington 700-footprint action with an ultra-compact 8-inch, 1:5 twist 338 ARC barrel. It provides the core assembly for a compact custom bolt-action rifle while allowing the customer to select the stock or chassis, trigger, bottom metal, and other components for the finished firearm.

The 8-inch configuration is the shortest CM7S 338 ARC barreled action currently offered by Chattahoochee Munitions. It is intended for customers who place a high priority on reducing overall system length, particularly when the finished rifle will be used with a suppressor.

Unlike the 12.5-inch configuration, which sits near the powder-utilization range CM has observed in testing, the 8-inch barrel intentionally trades some ballistic efficiency for a substantially shorter package. That tradeoff is the reason this 338 ARC Remage Barreled Action exists.

CM7S Action – Full PVD Coated

At the center of the system is the Chattahoochee Munitions CM7S action. The CM7S uses the familiar Remington 700 footprint while incorporating a three-lug bolt, 60-degree bolt throw, integrated recoil lug, M16-style extractor, and other features selected for a modern bolt-action platform.

• Remington 700 footprint
• 3-lug bolt design
• 60-degree bolt throw
• M16-style extractor
• One-piece .718″ diameter bolt body
• Wire EDM raceways
• Pinned 20 MOA Picatinny rail
• Large ejection port
• Lightweight action-body cutout
• .062″ firing pin
• Integrated .300″ recoil lug
• Tool-less fire-control removal
• Accepts Remington 700-pattern triggers
• 1-1/16″-16 barrel thread
• Side bolt-stop release
• Oversized bolt knob
• Spiral-fluted bolt
• Full PVD coating
• 25 oz action weight

8″ MÔS-Tek 338 ARC Barrel

The 338 ARC Remage Barreled Action is fitted with an 8-inch stainless-steel barrel manufactured for Chattahoochee Munitions by MÔS-Tek. The barrel uses 5R rifling, CM’s 1:5 twist specification, and the Remage barrel-nut system.

• 8″ barrel length
• 416R stainless steel
• 5R rifling
• 1:5 twist rate
• Shouldered crown
• 5/8×24 muzzle threads
• Remage barrel-nut system
• E100 Blackout Cerakote

Complete barreled-action weight: 49.21 oz / 3.07 lb

Weights and dimensions shown elsewhere in the product data may represent shipping dimensions rather than the physical dimensions of the barreled action.

Why a Remage 338 ARC Barreled Action?

The 338 ARC Remage Barreled Action combines the Remington 700 action footprint with a barrel-nut architecture commonly referred to as Remage. This gives the builder a familiar action footprint while retaining the barrel-nut configuration used throughout the CM7S system.

For a custom build, that means the customer can begin with the CM7S action and barrel already configured as a complete assembly while still selecting the remaining rifle components independently.

The CM7S accepts Remington 700-pattern triggers and can be installed into compatible Remington 700-footprint stocks and chassis systems.

Why CM Uses a 1:5 Twist

Chattahoochee Munitions specifies a 1:5 twist throughout the CM7S 338 ARC lineup, including the 8-inch configuration.

This is an intentional specification based on CM’s experience manufacturing and testing firearms using heavy .338-caliber projectiles. In our testing and experience, the faster twist has performed particularly well with heavy projectiles such as the 307-grain Hornady Sub-X.

The 1:5 twist is especially relevant in a compact 338 ARC Remage Barreled Action intended for heavy subsonic use, where projectile stability remains an important part of the complete system.

What the 8″ Configuration Is Designed to Do

The 8-inch CM7S is not simply a shorter version of the 16-inch barreled action. Its purpose is different.

In Chattahoochee Munitions’ experience with the 338 ARC loads and configurations we have evaluated, much of the useful powder utilization occurs around the 12-inch range. An 8-inch barrel therefore gives up some potential velocity and powder utilization compared with the 12.5-inch and 16-inch configurations.

In exchange, the builder gets a substantially shorter firearm. That can be especially valuable when the finished rifle will carry a suppressor, because reducing barrel length helps offset the overall length added at the muzzle.

For customers whose priority is maximum compactness rather than maximum velocity, the 8-inch 338 ARC Remage Barreled Action provides a distinct option within the CM7S family.

338 ARC in an Ultra-Compact Bolt Action

338 ARC was designed around the compact AR-15 cartridge envelope, but the cartridge also lends itself to compact bolt-action systems.

A manually operated firearm does not rely on propellant gas to cycle an action. That removes gas-system and buffer considerations from the equation and gives the builder a different operating envelope when configuring ammunition, barrel length, and suppressor use.

That characteristic becomes increasingly relevant as barrel length decreases. The 8-inch CM7S can be built around compact overall dimensions without the need to tune a semi-automatic operating system.

6.5 Grendel Type II Bolt Face and AICS Magazine System

The CM7S 338 ARC uses a 6.5 Grendel Type II .449″ bolt face. When installed in a compatible stock or chassis, the finished rifle is designed around an AICS-pattern magazine system.

Chattahoochee Munitions has already tested and selected the magazine used with its complete CM7S rifles. The 338 ARC Bolt Action Magazine is a 10-round MDT polymer AICS-pattern magazine tested by CM with 338 ARC.

Magazine compatibility is treated as part of the firearm system rather than something the customer should have to troubleshoot after completing the build.

A Compact Foundation for a Custom Rifle

The 338 ARC Remage Barreled Action allows the customer to start with the CM7S action and 8-inch barrel already assembled while retaining control over the remaining build components.

The Remington 700 footprint provides access to a broad ecosystem of compatible stocks, chassis systems, triggers, bottom metal, and accessories. The CM7S accepts Remington 700-pattern triggers, while the Remage architecture provides the barrel interface used across the CM7S platform.

This makes the 8-inch barreled action useful for a builder who wants CM’s compact 338 ARC configuration without purchasing a complete rifle.

338 ARC Subsonic and Suppressed Applications

The 8-inch CM7S is particularly relevant to customers building around heavy subsonic ammunition and suppressed use.

That does not mean an 8-inch barrel is the ballistic optimum for every 338 ARC load. Projectile construction, powder selection, ammunition, twist rate, suppressor configuration, and intended use all affect the finished system.

The tradeoff is straightforward: a shorter barrel reduces overall firearm length while giving up some potential velocity and powder utilization compared with longer configurations.

For a deeper technical discussion of 338 ARC, including barrel length, 1:8 versus 1:5 twist, suppression, subsonic versus supersonic ammunition, and comparisons with 300 Blackout and 8.6 Blackout, read our 338 ARC Subsonic guide.

Three CM7S 338 ARC Barreled Actions

Chattahoochee Munitions offers three CM7S barreled-action configurations, each serving a different role.

• 16″ – conventional rifle-length configuration
• 12.5″ – balance of compact dimensions and the powder-utilization characteristics observed in CM testing
• 8″ – maximum emphasis on reducing overall system length

All three use the CM7S action architecture and CM’s 1:5 twist specification.

Explore Containment Zone 338

The 8-inch 338 ARC Remage Barreled Action is part of the broader Chattahoochee Munitions 338 ARC ecosystem.

CM offers 338 ARC across CM7S bolt-action and CM15 AR-15 platforms, including complete firearms, barreled actions, upper receivers, and tested magazines. Explore the entire family in Containment Zone 338.

338 ARC Remage Barreled Action FAQ

What is a 338 ARC Remage Barreled Action?

The CM7S 338 ARC Remage Barreled Action combines a Remington 700-footprint CM7S action with a chambered 338 ARC barrel installed using a Remage barrel-nut system. It provides the core assembly for building a complete bolt-action rifle.

Why does CM offer an 8″ 338 ARC barrel?

The 8-inch version is intended for customers prioritizing minimum overall system length. It gives up some potential velocity and powder utilization compared with longer barrels in exchange for a substantially more compact configuration.

What twist rate does the 8″ CM7S use?

The 8-inch CM7S uses a 1:5 twist. Chattahoochee Munitions uses this twist rate throughout its CM7S 338 ARC lineup based on our experience with heavy .338-caliber projectiles.

Does the CM7S use a Remington 700 footprint?

Yes. The CM7S uses a Remington 700 footprint and accepts Remington 700-pattern triggers, providing access to a broad range of compatible custom-rifle components.

What magazine system does a completed CM7S 338 ARC use?

The finished CM7S uses an AICS-pattern magazine system. Chattahoochee Munitions uses a tested 10-round MDT polymer magazine with its complete CM7S 338 ARC firearms.

Is the 8″ configuration suitable for suppressed use?

Its short barrel makes it particularly useful for a compact suppressed build because the reduced barrel length helps offset the length added by a suppressor. Ammunition, projectile selection, suppressor choice, and the rest of the rifle configuration still determine the performance of the complete system.