CM15 338 ARC AR15 Rifle 16″ – Black Tungsten

CM15 338 ARC AR Rifle – 16″ Black Tungsten

The CM15 338 ARC AR Rifle is Chattahoochee Munitions’ 16-inch semi-automatic implementation of 338 ARC in the AR-15 platform. Built around CM15 billet 7075-T6 receivers, the rifle combines a 16-inch 1:8 twist barrel, adjustable gas and buffer systems, a low-mass bolt carrier group, and a TriggerTech AR15 Duty trigger.

This configuration features Black Tungsten Cerakote on the receivers, handguard, and receiver extension with Black B5 Systems furniture. The complete rifle weighs approximately 6 pounds 10 ounces with an unloaded magazine and no accessories, with an overall length of 33.25 to 36.50 inches.

The CM15 is designed as a complete operating system rather than simply adapting a barrel to an AR-15 receiver. The requisite bolt face, CM-vetted magazine, adjustable gas block, adjustable buffer, and purpose-built barrel are incorporated into the complete 338 ARC platform.

CM15 Billet Upper and Lower Receivers

The 338 ARC AR Rifle is built around the CM15 billet receiver set. Both receivers are CNC machined from 7075-T6 aluminum and incorporate ambidextrous controls and a widely flared magazine well.

• AR-15-pattern receiver architecture
• CNC machined from 7075-T6 billet aluminum
• Pictogram-style Fire/Safe markings on both sides
• Lightened fire-control-group faces and magazine well
• Integral trigger guard
• Machined, widely flared magazine well
• Ambidextrous safety
• Ambidextrous magazine release
• Ambidextrous bolt release
• CM15 pivot and takedown pins
• Black Tungsten Cerakote

TriggerTech AR15 Duty Trigger

The CM15 uses the TriggerTech AR15 Duty trigger. Customers can select from three trigger configurations:

• Single-stage straight bow
• Single-stage curved bow
• Two-stage straight bow

These choices provide both single-stage and two-stage options, along with straight- and curved-bow configurations.

CM15 Low-Mass Bolt Carrier Group

The CM15 338 ARC AR Rifle uses a low-mass bolt carrier group built around a 9310 steel bolt. The bolt incorporates the requisite 6.5 Grendel Type II / .449″ bolt face for the CM15 338 ARC system.

• 9310 steel bolt
• 6.5 Grendel Type II / .449″ bolt face
• High Pressure Tested (HPT) bolt
• Magnetic Particle Inspected (MPI) bolt
• Nitride-coated bolt
• Nitride-coated carrier
• Nitride-coated gas key
• Hardened gas key
• Grade 8 hardened gas-key fasteners
• Staked gas key
• Tool-steel extractor

CM Ambidextrous Charging Handle

The rifle is equipped with the CM Ambidextrous Charging Handle in collaboration with Breek Arms. Manufactured from 7075 aluminum, the charging handle provides ambidextrous operation from either side of the CM15.

16″ 338 ARC Barrel – 1:8 Twist

The 16-inch CM15 uses a CrMV barrel with a black nitride finish and 1:8 twist. The barrel incorporates a pistol-length gas system, .875-inch gas journal, shouldered crown, and 5/8×24 muzzle threads.

• 16″ barrel length
• CrMV steel
• Black nitride finish
• 1:8 twist rate
• Shouldered crown
• 5/8×24 muzzle threads
• .875″ gas journal
• Pistol-length gas system

Adjustable Gas and Buffer System

The 338 ARC AR Rifle uses an adjustable operating system. A Superlative Arms .875 adjustable gas block provides adjustment at the gas system, while the ODIN Works AR15 Lite Adjustable Buffer provides an additional tuning point at the receiver extension.

Using adjustable components at both locations allows the CM15 operating system to be configured rather than relying on a single fixed gas-and-buffer combination.

• Superlative Arms .875 adjustable gas block
• Melonite-treated pistol-length gas tube
• ODIN Works AR15 Lite Adjustable Buffer
• Adjustable buffer weight
• CM carbine receiver extension
• QD end plate

CM15 15″ M-LOK Handguard

The 16-inch rifle uses the CM15 LWS low-profile 15-inch handguard finished in Black Tungsten Cerakote.

• 6061 aluminum construction
• 15″ length
• Dual-taper attachment system
• Steel barrel nut
• QD sling attachment points at 3 and 9 o’clock
• M-LOK mounting surfaces on sides and bottom
• Full-length Picatinny top rail
• Black Tungsten Cerakote

B5 Systems Furniture

Black B5 Systems furniture completes the Black Tungsten configuration.

• B5 Systems Bravo stock – Black
• B5 Systems pistol grip – Black
• B5 Systems rail covers – Black
• CM receiver extension – Black Tungsten Cerakote
• QD end plate
• ODIN Works AR15 Lite Adjustable Buffer

338 ARC Muzzle Device Options

The barrel uses 5/8×24 muzzle threads for compatible .338-caliber muzzle devices. Available configurations may include mounting solutions from Q, Dead Air, Yankee Hill, SilencerCo, and other compatible systems. Contact Chattahoochee Munitions regarding specific muzzle-device selections or price adjustments.

10-Round 338 ARC AR-15 Magazine

The CM15 includes a 10-round DURAMAG SS AR-15-pattern magazine vetted by Chattahoochee Munitions for 338 ARC. The magazine uses 410 stainless-steel construction and is selected as part of the complete CM15 system. For optimal feeding and reliable operation, Chattahoochee Munitions recommends loading the magazine with no more than eight rounds.

Additional magazines are available through the CM 338 ARC AR15 Magazine product page.

Why a 16″ 338 ARC AR Rifle?

The 16-inch configuration provides a conventional rifle option within the CM15 family. In Chattahoochee Munitions testing of the 338 ARC loads we have evaluated, powder utilization occurs largely around the 12-inch barrel-length range. The 16-inch configuration therefore is not simply an exercise in adding barrel length to pursue velocity.

Instead, the 16-inch 338 ARC AR Rifle provides customers with a conventional rifle configuration while retaining the semi-automatic operation and AR-15 platform envelope that distinguish the CM15 from the CM7S bolt-action family.

A Purpose-Built 338 ARC AR Platform

338 ARC places a .338-caliber cartridge within the AR-15 platform envelope. The CM15 builds around that capability with components selected specifically for the cartridge and operating system.

The combination of a 6.5 Grendel Type II / .449″ bolt face, compatible magazine, adjustable gas block, adjustable buffer, and dedicated barrel creates a complete system rather than treating 338 ARC as simply a barrel conversion.

Customers can compare the CM15 semi-automatic platform with CM7S bolt-action systems through Containment Zone 338.

CM15 338 ARC AR Rifle Specifications

• Cartridge: 338 ARC
• Platform: CM15 / AR-15 pattern
• Operating system: Gas-operated semi-automatic
• Upper/lower: 7075-T6 billet aluminum
• Finish: Black Tungsten Cerakote
• Barrel: 16″ CrMV
• Barrel finish: Black nitride
• Twist: 1:8
• Muzzle thread: 5/8×24
• Gas journal: .875″
• Gas system: Pistol length
• Gas block: Superlative Arms .875 adjustable
• Buffer: ODIN Works AR15 Lite Adjustable Buffer
• Bolt: 9310 steel, HPT/MPI
• Bolt face: 6.5 Grendel Type II / .449″
• BCG: CM15 low-mass, nitride
• Charging handle: CM Ambidextrous Charging Handle in collaboration with Breek Arms
• Trigger: TriggerTech AR15 Duty
• Trigger options: Single-stage straight bow, single-stage curved bow, or two-stage straight bow
• Handguard: CM15 LWS 15″ M-LOK
• Stock: B5 Systems Bravo – Black
• Grip: B5 Systems – Black
• Magazine: 10-round DURAMAG SS, CM vetted for 338 ARC. For optimal feeding and reliable operation, Chattahoochee Munitions recommends loading the magazine with no more than eight rounds.
• Weight: 6 lb 10 oz with unloaded magazine and no accessories
• Overall length: 33.25″–36.50″
• Length of pull: 11.50″–14.75″

Explore Containment Zone 338

Visit Containment Zone 338 to compare CM15 semi-automatic rifles, CM7S bolt-action systems, compact configurations, barreled actions, magazines, and technical information about 338 ARC.

338 ARC AR Rifle FAQ

What is the CM15 338 ARC AR Rifle?
The CM15 is Chattahoochee Munitions’ gas-operated semi-automatic AR-15-pattern platform chambered in 338 ARC.

What twist rate does the 16-inch CM15 use?
The 16-inch CM15 uses a 1:8 twist CrMV barrel with a black nitride finish.

What bolt face does the CM15 use?
The CM15 uses a 9310 steel bolt incorporating the requisite 6.5 Grendel Type II / .449″ bolt face. The bolt is High Pressure Tested and Magnetic Particle Inspected.

What trigger is installed in the CM15?
The rifle uses a TriggerTech AR15 Duty trigger with single-stage straight, single-stage curved, and two-stage straight configurations available.

What charging handle does the CM15 use?
The rifle uses the CM Ambidextrous Charging Handle in collaboration with Breek Arms. The charging handle is manufactured from 7075 aluminum and provides ambidextrous operation.

Does the CM15 use an adjustable buffer?
Yes. The CM15 uses an ODIN Works AR15 Lite Adjustable Buffer together with a Superlative Arms .875 adjustable gas block.

What magazine is included?
The rifle includes a 10-round DURAMAG SS AR-15-pattern magazine vetted by Chattahoochee Munitions for 338 ARC. For optimal feeding and reliable operation, Chattahoochee Munitions recommends loading the magazine with no more than eight rounds.