CM7S 338 ARC Short Barreled Rifle – 12.5″ Black Tungsten
The CM7S 338 ARC Short Barreled Rifle combines a compact 12.5-inch barrel with the Chattahoochee Munitions CM7S bolt-action platform. Built around our Remington 700-footprint action, MÔS-Tek 1:5 twist barrel, TriggerTech Primary trigger, and CM7 billet chassis, this configuration provides a compact .338-caliber system for hunting, suppressed shooting, and general field use.
Chattahoochee Munitions has extensive experience building and testing heavy .338-caliber systems. Based on our testing of the 338 ARC loads we have evaluated, powder utilization occurs largely around the 12-inch barrel-length range. The 12.5-inch configuration therefore provides an effective balance between ballistic efficiency and compact overall length.
This 338 ARC Short Barreled Rifle features a Black Tungsten Cerakote chassis with black components. A pistol configuration with a telescoping Tailhook brace is also available.
CM7S Bolt Action – Full PVD Coating
The foundation of the 338 ARC Short Barreled Rifle is the Chattahoochee Munitions CM7S action. The CM7S uses the familiar Remington 700 footprint while incorporating features selected for precision, hunting, and demanding field use.
- Remington 700 footprint
- Three-lug bolt design
- 60-degree bolt throw
- M16-style extractor
- One-piece .718″ diameter bolt body
- Wire EDM raceways for consistent tolerances and smooth cycling
- Pinned 20 MOA Picatinny rail
- Large ejection port
- Lightweight action-body cutout
- .062″ firing pin
- Integrated .300″ recoil lug
- Tool-less fire-control removal
- Compatible with Remington 700-pattern triggers
- 1-1/16″-16 barrel thread
- Side bolt-stop release
- Oversize bolt knob
- Spiral-fluted bolt
- Full PVD coating
- 25 oz action weight
12.5″ MÔS-Tek 338 ARC Barrel – 1:5 Twist
The CM7S uses a MÔS-Tek custom bolt-action barrel manufactured from 416R stainless steel. Chattahoochee Munitions specifies a fast 1:5 twist rate for our CM7S 338 ARC systems.
- 12.5″ barrel length
- 416R stainless steel
- 5R rifling
- 1:5 twist rate
- Shouldered crown
- 5/8×24 muzzle threads
- Remage barrel-nut mounting system
- E100 Blackout Cerakote
Why Chattahoochee Munitions Uses a 1:5 Twist
The standardized 338 ARC specification uses 1:8 as a practical twist-rate baseline. Chattahoochee Munitions takes a different approach with our bolt-action platform. Based on our experience manufacturing and testing heavy .338-caliber systems, including extensive work with 8.6 Blackout, we specify a 1:5 twist for the CM7S.
In Chattahoochee Munitions testing, the faster twist has performed particularly well with heavy .338-caliber projectiles such as the Hornady 307-grain Sub-X. The 1:5 twist is therefore a deliberate CM specification based on our intended use of the platform rather than simply duplicating the standardized 1:8 configuration.
TriggerTech Remington 700 Primary Trigger
The 338 ARC Short Barreled Rifle is equipped with a TriggerTech Remington 700 Primary trigger. Flat and curved trigger options are available, with pull weight externally adjustable from approximately 1.5 to 4.0 pounds.
TriggerTech’s Frictionless Release Technology provides a crisp break and short overtravel. Hardened 440C stainless-steel internal components provide corrosion resistance and durability, while CLKR Technology provides defined pull-weight adjustment.
CM7 Billet Chassis – Black Tungsten
The CM7 chassis provides a rigid aluminum foundation for the compact bolt-action system while retaining extensive accessory and configuration flexibility.
- Machined from a single block of billet aluminum
- Flared magazine well for AICS-pattern magazines
- Ambidextrous magazine release
- AR-15 pistol-grip compatibility without an integrated dovetail
- Large trigger guard for gloved operation
- Modular single-bolt stock/brace adapter system
- M-LOK accessory mounting
- Dual integrated QD sling sockets
- Full-length bottom ARCA rail
- Black Tungsten Cerakote
SBR or Pistol Configuration
The 12.5-inch CM7S can be configured according to the customer’s intended application.
SBR configuration: Telescoping buttpad with adjustable cheek riser. Short Barreled Rifle configurations are subject to applicable federal, state, and local requirements and require transfer through an appropriately licensed dealer.
Pistol configuration: Telescoping Tailhook brace with adjustable cheek riser.
CM Precision Vertical Crossover Grip
The chassis is fitted with the CM Precision Vertical Crossover Grip, developed in collaboration with MK Machining. Its near-vertical geometry complements the compact CM7S chassis and provides a natural interface across a variety of shooting positions.
10-Round AICS-Pattern Magazine
Each 338 ARC Short Barreled Rifle includes a 10-round MDT polymer 6 ARC AICS-pattern magazine. Chattahoochee Munitions has tested this magazine architecture with 22 ARC, 6 ARC, and 338 ARC in our bolt-action systems.
Why a 12.5″ 338 ARC?
Barrel length is an important part of configuring a compact 338 ARC system. Based on Chattahoochee Munitions testing of the loads we have evaluated, powder utilization occurs largely around the 12-inch barrel-length range.
The 12.5-inch barrel therefore occupies an attractive middle ground. It provides additional barrel length over our shortest CM7S configurations while remaining substantially more compact than a conventional 16-inch rifle.
For customers seeking a shoulder-fired compact bolt-action system, the 338 ARC Short Barreled Rifle combines the CM7S action and 1:5 twist barrel in a package measuring as little as approximately 26 inches overall depending on configuration.
Subsonic and Supersonic Capability
The CM7S is not limited to one side of the 338 ARC performance envelope. The cartridge supports both subsonic and supersonic ammunition, allowing the same platform to serve different applications.
Chattahoochee Munitions places particular emphasis on subsonic-capable firearm systems. The combination of a manually operated bolt action, compact 12.5-inch barrel, and fast 1:5 twist makes this configuration particularly relevant to shooters interested in heavy .338-caliber subsonic projectiles.
CM7S 338 ARC Short Barreled Rifle Specifications
- Cartridge: 338 ARC
- Action: Chattahoochee Munitions CM7S
- Action footprint: Remington 700
- Bolt: Three-lug, 60-degree throw
- Bolt face: 6.5 Grendel Type II / .449″
- Barrel: 12.5″ MÔS-Tek 416R stainless steel
- Rifling: 5R
- Twist: 1:5
- Muzzle thread: 5/8×24
- Barrel finish: E100 Blackout Cerakote
- Trigger: TriggerTech Remington 700 Primary
- Trigger adjustment: 1.5–4.0 lb
- Chassis: CM7 billet aluminum
- Chassis finish: Black Tungsten Cerakote
- Magazine: 10-round MDT polymer 6 ARC AICS-pattern magazine
- Weight: 6 lb 6 oz
- Overall length: 26.0″–32.50″
- Length of pull: 6.0″–13.5″
Explore Containment Zone 338
The CM7S is part of the larger Chattahoochee Munitions 338 ARC platform family. Visit Containment Zone 338 to explore CM7S bolt-action firearms, CM15 AR-15 systems, barreled actions, magazines, and technical information about the cartridge.
338 ARC Short Barreled Rifle FAQ
What barrel length does the CM7S 338 ARC Short Barreled Rifle use?
This configuration uses a 12.5-inch MÔS-Tek 416R stainless-steel barrel with 5R rifling and a 1:5 twist.
Why does Chattahoochee Munitions use a 1:5 twist?
CM specifies the faster twist based on our testing and experience with heavy .338-caliber projectiles and subsonic systems. In our testing, the 1:5 twist has performed particularly well with heavy projectiles such as the 307-grain Hornady Sub-X.
Can this CM7S also be configured as a pistol?
Yes. The 12.5-inch CM7S can be configured as a pistol with a telescoping Tailhook brace or as an SBR with a telescoping buttpad, subject to applicable laws and transfer requirements.
What magazine does the CM7S use?
The firearm includes a 10-round MDT polymer 6 ARC AICS-pattern magazine that Chattahoochee Munitions has tested with 338 ARC in the CM7S platform.
Can the CM7S use subsonic and supersonic 338 ARC ammunition?
Yes. The CM7S can use both subsonic and supersonic 338 ARC ammunition. Its 1:5 twist specification is particularly oriented toward performance with heavy .338-caliber projectiles.
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