8.6 Short Barrel Rifle | CM7S 12.5″ WOOX Walnut
NFA ITEM: This firearm is configured as a short-barreled rifle (SBR) and is subject to applicable federal, state and local requirements. Transfer must be completed through the appropriate licensed dealer and in accordance with applicable NFA requirements.
The CM7S 8.6 Short Barrel Rifle combines a 12.5-inch 8.6 Blackout barrel with the Chattahoochee Munitions CM7S action and WOOX walnut chassis system. It provides a compact bolt-action configuration while retaining an adjustable walnut stock, AICS-pattern magazine architecture and modern accessory mounting provisions.
The 12.5-inch barrel is particularly relevant to the way CM approaches 8.6 Blackout. In the subsonic loads we have evaluated, powder utilization is effectively complete at approximately 12 to 12.5 inches. That makes this configuration a practical balance between compact overall length and the ballistic requirements of the cartridge.
CM offers both 1:3 and 1:5 twist rates, allowing the rifle to be configured around the projectile and ammunition the customer intends to use rather than treating one twist rate as universally correct for every 8.6 BLK application.
CM7S Bolt Action
At the center of this 8.6 Short Barrel Rifle is the Chattahoochee Munitions CM7S action. The CM7S uses a Remington 700 footprint with a three-lug bolt and 60-degree throw in a purpose-built action used throughout our bolt-action firearm family.
- Remington 700 footprint
- Three-lug bolt design
- 60-degree bolt throw
- M16-style extractor
- One-piece .718″ 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-style triggers
- 1-1/16″-16 barrel thread
- Side bolt-stop release
- Oversized bolt knob
- Spiral-fluted bolt
- Full PVD coating
- Action weight: 25 oz
The short 60-degree bolt lift complements the compact 12.5-inch configuration while the pinned 20 MOA rail provides an integrated optic-mounting foundation.
12.5″ Mos-Tek 8.6 Blackout Barrel
This CM7S is fitted with a 12.5-inch Mos-Tek premium bolt-action barrel manufactured from 416R stainless steel with 5R rifling.
- 12.5″ barrel length
- 416R stainless steel
- 5R rifling
- Choice of 1:3 or 1:5 twist
- Shouldered crown
- 5/8×24 muzzle threads
- Remage barrel-nut mounting system
- E100 Blackout Cerakote
CM offers both twist rates because projectile selection matters. In our testing with barrels approximately 12.5 inches or longer, 1:5 twist has generally performed well with projectiles around 300 grains or less, while 1:3 twist has generally been better suited to heavy subsonic projectiles around 323 grains and above. Projectile construction, length, ammunition and velocity can also influence stabilization.
For a deeper discussion of CM’s experience with barrel length, projectile weight, twist selection and suppression, see our 8.6 Blackout Subsonic Guide.
TriggerTech Remington 700 Primary Trigger
The CM7S 8.6 Short Barrel Rifle is equipped with a TriggerTech Remington 700 Primary trigger, available in either a flat or curved configuration.
The Primary provides an adjustable pull-weight range of approximately 1.5 to 4.0 pounds. The CM7S action also accepts compatible Remington 700-style triggers, providing additional options for customers who may choose a different trigger configuration later.
WOOX Walnut Chassis System
The WOOX configuration combines walnut furniture with an aluminum structural system, giving this compact CM7S a distinctly different character from our standard billet-chassis rifles. It retains the adjustability and accessory provisions of a modern rifle while providing the feel and appearance of walnut.
WOOX Exactus Stock
- Walnut construction
- Adjustable cheek riser
- Adjustable buttpad height
- Adjustable length of pull
- Bottom Picatinny rail
- QD sling mount
WOOX Furiosa Forend
- Walnut exterior
- M-LOK at 3, 6 and 9 o’clock positions
WOOX Monocore
- M5 bottom-metal configuration
- AICS magazine compatible
The result is an 8.6 Short Barrel Rifle that combines the reduced barrel length of the 12.5-inch CM7S with the ergonomics and appearance of the WOOX walnut system.
Vetted AICS Magazine System
The CM7S uses an AICS-pattern magazine architecture. Reliable feeding is part of the complete firearm configuration, so CM uses a vetted magazine solution rather than leaving magazine compatibility to customer experimentation.
This rifle includes a 5-round AICS-pattern magazine. Additional CM 8.6 Blackout Magazines are available for the bolt-action platform.
Why a 12.5″ 8.6 Blackout SBR?
The 12.5-inch configuration is an important part of the CM 8.6 Blackout lineup because it provides a substantial reduction in barrel length compared with the 16-inch rifle while remaining within the barrel-length range where our tested subsonic loads have shown effectively complete powder utilization.
That makes the 12.5-inch barrel especially relevant for a compact suppressed bolt-action system. The threaded 5/8×24 muzzle provides compatibility with appropriately configured muzzle devices and suppressor mounting systems.
A bolt-action platform also removes the gas-system and buffer-system variables associated with cycling a semi-automatic firearm. When changing appropriate ammunition or suppressor configurations, the shooter does not have to tune the operating system to maintain semi-automatic cycling.
Compact 8.6 Blackout with Walnut Furniture
Most compact rifles use highly utilitarian furniture. The WOOX configuration takes a different approach by combining the 12.5-inch CM7S with walnut while retaining adjustable cheek height, adjustable length of pull and modern accessory mounting.
At 7 lb 12 oz with an overall length of approximately 31.75 to 32.50 inches, this configuration is substantially more compact than the 16-inch WOOX while retaining the same CM7S action architecture and WOOX furniture system.
The adjustable Exactus stock provides a length-of-pull range of approximately 13.75 to 14.75 inches, allowing the rifle to be fitted around the shooter and optic configuration.
Built as a Complete 8.6 Blackout System
A well-configured 8.6 Short Barrel Rifle involves more than reducing barrel length. Twist rate, projectile selection, magazine compatibility, suppressor choice and intended ammunition all influence the characteristics of the finished firearm.
CM has been building 8.6 Blackout firearms since the cartridge’s early introduction, before SAAMI standardization. That experience is why we offer both major twist-rate options and provide a vetted magazine solution rather than expecting the customer to determine compatibility after purchasing the firearm.
To compare this WOOX SBR with our 16-inch rifles, other compact CM7S configurations, CM10 AR10 platforms and supporting components, visit Area 8.6.
CM7S 12.5″ WOOX Specifications
| Platform | CM7S Bolt Action |
|---|---|
| Caliber | 8.6 Blackout |
| Configuration | Short-Barreled Rifle (SBR) |
| Barrel Length | 12.5″ |
| Barrel Manufacturer | Mos-Tek |
| Barrel Material | 416R Stainless Steel |
| Rifling | 5R |
| Twist Rate | 1:3 or 1:5 |
| Muzzle Threads | 5/8×24 |
| Trigger | TriggerTech Remington 700 Primary |
| Stock | WOOX Exactus Walnut |
| Forend | WOOX Furiosa Walnut |
| Magazine Pattern | AICS |
| Included Magazine | 5-Round AICS Pattern |
| Weight | 7 lb 12 oz |
| Overall Length | 31.75″ – 32.50″ |
| Length of Pull | 13.75″ – 14.75″ |
8.6 Short Barrel Rifle FAQ
Is the CM7S 12.5″ WOOX an SBR?
Yes. This configuration has a shoulder stock and a 12.5-inch barrel and is sold as a short-barreled rifle (SBR). It is an NFA-regulated firearm and must be transferred in accordance with applicable federal, state and local requirements.
Why does CM use a 12.5″ barrel for this 8.6 Blackout SBR?
In the subsonic loads CM has evaluated, powder utilization is effectively complete at approximately 12 to 12.5 inches. The 12.5-inch configuration therefore provides a compact platform without simply shortening the barrel without regard to the ammunition being used.
What twist rate should I choose?
CM offers both 1:3 and 1:5 twist. In our testing with barrels approximately 12.5 inches and longer, 1:5 has generally performed well with projectiles around 300 grains or less, while 1:3 has generally been better suited to heavy subsonic projectiles around 323 grains and above. Projectile design, length, ammunition and velocity should also be considered.
Can the CM7S WOOX SBR be suppressed?
Yes. The barrel uses 5/8×24 muzzle threads for compatible muzzle devices and suppressor mounting systems. Compatibility should always be verified for the specific suppressor, ammunition and firearm configuration.
What magazine does the rifle use?
The CM7S uses an AICS-pattern magazine system. This WOOX configuration includes a 5-round magazine, and CM offers additional vetted 8.6 Blackout Magazines.
Where can I compare other CM 8.6 Blackout configurations?
Visit Area 8.6 to compare the WOOX SBR with CM7S rifles, other compact bolt-action configurations and CM10 AR10 platforms.
NFA NOTICE: This firearm is configured as a short-barreled rifle and is subject to applicable federal, state and local requirements. Transfer must be completed through the appropriate licensed dealer and in accordance with applicable NFA requirements.
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