8.6 BLK AR10 Magazine | CM10 20-Round
The 8.6 BLK AR10 Magazine offered by Chattahoochee Munitions is the 20-round SR25-pattern magazine we use and vet for the CM10 8.6 Blackout platform. Built on the Magpul PMAG 20 LR/SR GEN M3 Window, it combines 20-round capacity with transparent MagLevel windows for quickly estimating the number of rounds remaining.
Chattahoochee Munitions has been building 8.6 Blackout firearms since the cartridge’s early introduction. During that time, magazine selection and feed geometry have been treated as parts of the complete firearm system rather than independent components.
This 8.6 BLK AR10 Magazine is intended for CM10 rifles, pistols and SBR configurations using conventional SR25-pattern magazine architecture. It is not an AICS magazine and is not intended for the CM7S bolt-action platform.
CM-Vetted 20-Round Magazine for 8.6 Blackout
The CM10 is a large-frame semi-automatic platform using SR25-pattern magazines. CM combines vetted magazines with customized feed ramps designed around feeding the large .338-caliber projectiles used by 8.6 Blackout.
Rather than simply offering a generic large-frame magazine based on published compatibility, CM offers magazines that we use with our own 8.6 Blackout firearms. The magazine, cartridge presentation, feed ramps and operating system are treated as parts of the complete CM10 configuration.
- CM-vetted for the CM10 8.6 Blackout platform
- SR25 / LR/SR-pattern magazine
- 20-round capacity
- Magpul PMAG 20 LR/SR GEN M3 Window platform
- Dual-side transparent MagLevel windows
- Impact- and crush-resistant polymer construction
- Constant-curve internal geometry
- Stainless-steel spring
- Self-lubricating anti-tilt follower
- Removable flared floorplate
- Tool-less disassembly
20-Round CM10 Magazine Capacity
This 8.6 BLK AR10 Magazine provides twice the capacity of the 10-round CM10 magazine option while retaining the familiar SR25-pattern form factor.
The 20-round configuration is the higher-capacity option for customers who want additional ammunition available before a magazine change. Customers who prefer a shorter magazine profile for hunting, bench shooting, bipod use or other applications can instead select CM’s 10-round magazine.
Both magazines use the same SR25-pattern architecture required by the CM10. The primary choice is therefore between the compact profile of the 10-round magazine and the additional capacity of this 20-round version.
MagLevel Window System
The Magpul PMAG 20 LR/SR GEN M3 Window incorporates transparent windows on both sides of the magazine body. A high-visibility indicator coil on the spring works with numerical markings on the magazine body to provide an approximate visual indication of remaining ammunition.
This MagLevel system gives the 20-round 8.6 BLK AR10 Magazine an additional feature not found on CM’s standard 10-round magazine option: the shooter can estimate remaining magazine capacity without removing cartridges from the magazine.
8.6 BLK AR10 Magazine Compatibility
This magazine is intended for the Chattahoochee Munitions CM10 8.6 Blackout platform and compatible firearms using SR25-pattern magazine architecture.
Within the CM lineup, it is appropriate for the complete range of CM10 8.6 Blackout configurations, including:
- 16″ CM10 8.6 Blackout rifles
- 12.5″ CM10 8.6 Blackout SBR configurations
- 8″ CM10 8.6 Blackout pistol configurations
CM10 8.6 Blackout firearms use conventional SR25-pattern magazines together with customized feed ramps for large .338-caliber projectiles.
CM10 vs. CM7S Magazine Architecture
CM builds 8.6 Blackout on both semi-automatic and bolt-action platforms, but those platforms use different magazine systems.
The CM10 is a large-frame semi-automatic platform and uses this SR25-pattern 8.6 BLK AR10 Magazine. The CM7S is a bolt-action platform and uses an AICS-pattern short-action magazine.
The two magazine types are not interchangeable.
CM7S owners should use the CM7S 8.6 Blackout Magazine.
10-Round vs. 20-Round CM10 Magazine
CM offers both 10-round and 20-round magazine options for the CM10 8.6 Blackout platform.
| Feature | 10-Round CM10 Magazine | 20-Round CM10 Magazine |
|---|---|---|
| Pattern | SR25 / LR/SR | SR25 / LR/SR |
| Capacity | 10 Rounds | 20 Rounds |
| Profile | Shorter | Full 20-Round |
| Window | No | Dual-Side MagLevel Windows |
| CM Platform | CM10 | CM10 |
Choose the 10-round version when a shorter magazine profile is preferred. Choose the 20-round 8.6 BLK AR10 Magazine when additional capacity and the MagLevel window system are priorities.
PMAG 20 LR/SR GEN M3 Window Construction
The underlying magazine is Magpul’s PMAG 20 LR/SR GEN M3 Window. Its polymer body uses constant-curve internal geometry with a stainless-steel spring and self-lubricating anti-tilt follower.
- 20-round capacity
- Dual transparent magazine windows
- MagLevel ammunition indicator system
- Constant-curve internal geometry
- Impact- and crush-resistant polymer body
- Stainless-steel corrosion-resistant spring
- Self-lubricating anti-tilt follower
- Textured front and rear gripping surfaces
- Paint-pen dot matrix for identification
- Flared removable floorplate
- Tool-less disassembly for cleaning
For additional manufacturer specifications, visit Magpul.
Part of the CM10 8.6 Blackout System
The 8.6 BLK AR10 Magazine is one component of the complete CM10 feeding and operating system. CM10 8.6 Blackout firearms combine vetted SR25-pattern magazines with customized feed ramps, selectable 1:3 or 1:5 twist barrels, adjustable gas and adjustable buffer weight.
For CM’s first-party observations about barrel length, projectile weight, twist rate and suppressed configurations, read the 8.6 Blackout Subsonic Guide.
To compare CM10 semi-automatic firearms, CM7S bolt-action firearms, barreled actions and supporting components, visit Area 8.6.
8.6 BLK AR10 Magazine Specifications
| CM Application | CM10 8.6 Blackout |
|---|---|
| Magazine Platform | Magpul PMAG 20 LR/SR GEN M3 Window |
| Pattern | SR25 / LR/SR |
| Capacity | 20 Rounds |
| Construction | Polymer |
| Window | Dual-Side Transparent MagLevel Windows |
| Body Geometry | Constant Curve |
| Follower | Self-Lubricating Anti-Tilt |
| Spring | Stainless Steel |
| Floorplate | Removable / Flared |
| CM Platform | CM10 |
8.6 BLK AR10 Magazine FAQ
What magazine does the CM10 8.6 Blackout use?
The CM10 uses conventional SR25-pattern magazines. This 20-round Magpul PMAG 20 LR/SR GEN M3 Window is a CM-vetted 8.6 BLK AR10 Magazine for the CM10 platform.
How many rounds does this magazine hold?
This magazine has a 20-round capacity.
What do the windows on the magazine show?
The transparent windows work with Magpul’s MagLevel system to provide an approximate visual indication of the number of rounds remaining in the magazine.
Will this magazine work in the CM7S?
No. The CM7S uses AICS-pattern magazines. This magazine uses SR25-pattern architecture for the semi-automatic CM10 platform.
Does CM offer a shorter 10-round magazine?
Yes. CM also offers a 10-round SR25-pattern magazine for the CM10. It provides the same basic magazine architecture in a shorter profile for customers who do not require 20-round capacity.
Why is this listed as an 8.6 Blackout magazine when the PMAG was developed for 7.62/.308?
The underlying PMAG is not exclusive to 8.6 Blackout. CM identifies it as an 8.6 Blackout magazine because it is an SR25-pattern magazine CM uses and vets within the CM10 8.6 Blackout firearm system.
Where can I compare CM’s 8.6 Blackout firearms and components?
Visit Area 8.6 for the complete Chattahoochee Munitions 8.6 Blackout lineup.
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