8.6 Blackout SBR | CM10 AR10 12.5″
The CM10 8.6 Blackout SBR is a compact large-frame semi-automatic built around a 12.5-inch 8.6 Blackout barrel, adjustable operating system and suppressor-oriented configuration. This version combines FDE Metallic Cerakote with Coyote B5 Systems furniture.
Chattahoochee Munitions has been building 8.6 Blackout firearms since the cartridge’s early introduction across both AR and bolt-action platforms. That experience has shaped the CM10 as a complete system incorporating SR25-pattern magazines, customized feed ramps for large .338-caliber projectiles, selectable barrel twist, adjustable gas and adjustable buffer weight.
The 12.5-inch barrel is particularly relevant to CM’s subsonic testing. In the subsonic loads we have evaluated, powder utilization has been effectively complete at approximately 12 to 12.5 inches. For a suppressed firearm, that provides a useful balance between barrel length and overall system length.
This firearm is primarily offered as an SBR and may also be configured as a pistol where applicable. Configuration-specific receiver-extension components vary with the selected setup.
CM10 Billet Receiver Set
The foundation of the 8.6 Blackout SBR is the CM10 billet receiver set. It uses conventional SR25-pattern magazine architecture with DPMS High Profile specifications.
- CNC machined from 7075-T6 billet aluminum
- SR25-pattern magazine architecture
- DPMS High Profile component specifications
- 16 TPI barrel-nut specification
- Lightweight fire-control-group faces and magazine well
- Weight-reduction cuts on upper receiver
- No forward assist
- Ambidextrous pictogram-style Fire/Safe engravings
- Integral trigger guard
- Machined magazine well with wide flare
- FDE Metallic Cerakote
TriggerTech Duty Trigger Options
The CM10 uses the TriggerTech Duty trigger family. Customers can select the trigger configuration that best matches their preference:
- TriggerTech Duty single-stage straight trigger
- TriggerTech Duty single-stage curved trigger
- TriggerTech Duty two-stage straight trigger
CM10 Lower Components
- CM ambidextrous safety
- CM ambidextrous magazine release
- CM10 pivot and takedown pins
- TriggerTech Duty trigger — selectable configuration
- CM10 ambidextrous bolt release
- B5 Systems Coyote grip
Adjustable Gas and Buffer System
A suppressed semi-automatic 8.6 Blackout firearm may require different operating-system settings depending on ammunition, projectile weight and suppressor configuration. The CM10 8.6 Blackout SBR provides adjustment through both the gas system and reciprocating mass.
A Superlative Arms .875 Adjustable Gas Block controls gas delivery, while the ODIN Works AR10 Adjustable Buffer allows adjustment of buffer weight.
These two tuning points allow the CM10 to be configured around the actual ammunition and suppressor combination being used rather than relying on one fixed operating setup.
Receiver Extension
The pistol configuration uses the SBPDW system shown in the product imagery. SBR configuration uses the appropriate stock system selected for the firearm.
- SBPDW brace on pistol configuration
- Three-position adjustment
- QD attachment at 6 o’clock
- FDE Metallic Cerakote
- Phase 5 Coyote strap
- ODIN Works AR10 Adjustable Buffer
CM10 Bolt Carrier Group
The CM10 upper uses a bolt carrier group with weight-reduction cuts as part of the rifle’s adjustable operating system.
- 9310 steel bolt
- High-pressure tested bolt
- Magnetic-particle-inspected bolt
- Shot-peened 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
- T.E.A. extractor spring
- Black extractor insert
- Crane O-ring
CM also incorporates customized feed ramps designed around feeding the large .338-caliber projectiles used by 8.6 Blackout.
12.5″ Mos-Tek 8.6 Blackout Barrel
The 8.6 Blackout SBR uses a 12.5-inch barrel produced in collaboration with Mos-Tek.
- 12.5″ barrel length
- 416R stainless steel
- 5R rifling
- Choice of 1:3 or 1:5 twist
- Shouldered crown
- M18x1.5 muzzle threads
- .875 gas journal
- E100 Blackout Cerakote finish
CM offers both 1:3 and 1:5 twist because projectile construction, weight, length and velocity influence stabilization. In CM testing around this barrel length, projectiles around 300 grains and lighter have generally stabilized well with 1:5 twist, while heavier subsonic projectiles around 323 grains and above have generally favored 1:3 twist. These are practical observations from the loads we have evaluated rather than universal rules.
For a deeper look at barrel length, twist rate, projectile weight and suppressed performance, read the 8.6 Blackout Subsonic Guide.
SLR 11.3″ Handguard Options
The 12.5-inch CM10 uses an SLR 11.3-inch handguard system rather than the longer CM10 LWS handguard used on the 16-inch rifles. This keeps the standard handguard behind the muzzle while maintaining a compact package for suppressor mounting.
SLR ZRO 11.3″ M-LOK
The standard option is the SLR ZRO 11.3″ M-LOK Handguard.
- 11.3″ length
- 7075 aluminum barrel nut
- 6061 aluminum handguard
- 1.4″ internal diameter
- QD attachment at 3 and 9 o’clock positions
- M-LOK attachment surfaces on sides and bottom
- Full Picatinny top rail
- Free-floating design
SLR SD ZRO 11.3″ / 15.3″ OAL
An SLR SD ZRO configuration is also available for compatible suppressor setups.
- 11.3″ length to muzzle area
- 15.3″ overall length
- 7075 aluminum barrel nut
- 6061 aluminum handguard
- 1.8″ internal diameter
- QD attachment at 3 and 9 o’clock positions
- M-LOK attachment surfaces on sides and bottom
- Full Picatinny top rail
- Free-floating design
The larger 1.8-inch internal diameter and extended geometry allow the SD handguard to accommodate compatible suppressor configurations when suppressor dimensions and mounting geometry permit.
CM10 Upper Components
- CM10 ambidextrous charging handle — 7075 aluminum
- CM pistol-length gas tube — Melonite
- Superlative Arms .875 Adjustable Gas Block — Melonite
- SLR 11.3″ handguard system — selectable configuration
- B5 Systems Coyote rail covers
The M18x1.5 muzzle threads allow the firearm to be configured with an appropriate compatible muzzle device or suppressor mounting system.
Why a 12.5″ 8.6 Blackout SBR?
The 12.5-inch barrel is a deliberate choice for this 8.6 Blackout SBR. In the subsonic loads CM has evaluated, powder utilization has been effectively complete at approximately 12 to 12.5 inches.
This allows the firearm to remain substantially shorter than a conventional 16-inch rifle after a suppressor is added while retaining the barrel-length range that has performed well in CM’s subsonic testing.
Rather than treating barrel length as an isolated specification, CM approaches the 12.5-inch platform as a complete suppressed system incorporating barrel length, twist rate, gas adjustment, buffer adjustment, magazine selection and suppressor configuration.
SR25-Pattern Magazine Architecture
The CM10 uses SR25-pattern magazines rather than the AICS center-feed architecture used by CM’s large-frame 375 Raptor and 458 SOCOM XL platforms.
This firearm includes one 20-round 7.62 PMAG in Coyote. Additional vetted 20-round CM10 8.6 Blackout magazines are available separately.
CM10 12.5″ 8.6 Blackout SBR Specifications
| Platform | CM10 Large-Frame Semi-Automatic |
|---|---|
| Caliber | 8.6 Blackout |
| Configuration | SBR or Pistol |
| Receiver Pattern | SR25 / DPMS High Profile |
| Receiver Material | 7075-T6 Billet Aluminum |
| Receiver Finish | FDE Metallic Cerakote |
| Barrel Length | 12.5″ |
| Barrel Manufacturer | Mos-Tek / CM Collaboration |
| Barrel Material | 416R Stainless Steel |
| Barrel Finish | E100 Blackout Cerakote |
| Rifling | 5R |
| Twist | 1:3 or 1:5 |
| Muzzle Threads | M18x1.5 |
| Gas Journal | .875″ |
| Gas System | Pistol Length |
| Gas Block | Superlative Arms .875 Adjustable — Melonite |
| Buffer | ODIN Works AR10 Adjustable |
| Trigger | TriggerTech Duty — Single-Stage Straight, Single-Stage Curved or Two-Stage Straight |
| Handguard | SLR ZRO 11.3″ or SLR SD ZRO 11.3″ / 15.3″ OAL |
| Magazine | 1x 20-Round PMAG 7.62 — Coyote |
| Overall Length | 29.625″–32.125″ |
| Weight | 8 lb 3 oz with unloaded magazine and no accessories |
| Length of Pull | 10.75″–13.25″ |
8.6 Blackout SBR FAQ
Why does CM use a 12.5-inch barrel?
In the subsonic loads CM has evaluated, powder utilization has been effectively complete at approximately 12 to 12.5 inches. This makes the 12.5-inch barrel a practical balance between subsonic performance and compact suppressed overall length.
Can the CM10 12.5″ also be configured as a pistol?
Yes. The firearm can be configured as an SBR or pistol where applicable. Configuration-specific stock or brace components depend on the selected setup and applicable requirements.
What trigger comes with the CM10?
The CM10 uses the TriggerTech Duty trigger family with single-stage straight, single-stage curved and two-stage straight options.
What makes the 12.5″ handguard configuration different?
The 12.5-inch firearms use SLR 11.3-inch handguard systems rather than the longer handguards used on the 16-inch CM10 rifles. The standard ZRO keeps the muzzle ahead of the handguard, while the larger-diameter SD ZRO can accommodate compatible suppressor configurations.
Should I choose 1:3 or 1:5 twist?
Twist selection depends on projectile construction, weight, length, ammunition and velocity. In CM testing around this barrel length, projectiles around 300 grains and lighter have generally stabilized well with 1:5 twist, while heavier subsonic projectiles around 323 grains and above have generally favored 1:3 twist. These are testing observations rather than universal rules.
What magazine does the CM10 use?
The CM10 uses SR25-pattern magazines. This firearm includes one 20-round 7.62 PMAG in Coyote, and additional vetted 20-round CM10 8.6 Blackout magazines are available separately.
Where can I compare other CM 8.6 Blackout firearms?
Visit Area 8.6 to compare the CM10 semi-automatic family, CM7S bolt-action platforms, barreled actions and supporting components.
Limited Lifetime Warranty
Chattahoochee Munitions provides a limited lifetime warranty to the original purchaser covering functional performance in the firearm’s original configuration. See the current CM warranty terms for complete details.
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