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Magpul PMAG AR-15 300 B Gen M3 20 Rounds Black
Our editorial team reviews specifications, product data, and field-use information to keep pages accurate.
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SKU: MAG1182-BLK-840815132233
Overview
Built for .300 AAC Blackout use in AR-pattern rifles, this magazine is intended for shooters who want a dedicated option for that cartridge rather than a general-purpose .223/5.56 mag. Its Gen M3 design includes visual and tactical differences to help distinguish it from other magazines, which can be useful when keeping multiple loads or calibers organized. The constant-curve geometry, ribbed gripping surface, aggressive front and rear texture, and paint pen dot matrix panel are all practical touches for range work, training, or field use where quick handling and clear identification matter. It is a purpose-built 20-round magazine in matte black, so capacity and cartridge-specific compatibility are the main considerations.
Why Hunters Choose the Magpul
Purpose-built .300
AAC Blackout cartridges in AR-15
20-round Capacity
Suits compact loadouts and controlled
Visual Tactical
Differences help distinguish .300 BLK
Gen M3
Features and performance are carried
Constant-curve Geometry
Supports the magazine’s dedicated .300
Key Features
- Purpose-built magazine for .300 AAC Blackout cartridges.
- 20-round capacity for AR-15 pattern use.
- Gen M3 design with the same features and performance as the Gen M3 line.
- Constant-curve geometry for the .300 BLK platform.
- Ribbed gripping surface with aggressive front and rear texture.
- Paint pen dot matrix panel on the lower label for magazine identification.
- Matte black finish with visual and tactical differences from standard magazines.
Best Used For
- .300 AAC Blackout AR-15 owners needing a purpose-built magazine for dedicated Blackout setups
- Hunters using subsonic or supersonic .300 BLK loads in compatible AR-pattern rifles
- Shooters who want clear visual differentiation between .300 BLK magazines and other AR magazines
- Users building a compact 20-round magazine setup for range work or field carry
- Suppressor users seeking a magazine designed around .300 AAC Blackout cartridge compatibility
Specifications
| Blade Finish | Matte Black |
|---|---|
| Cartridge | .300 AAC Blackout |
| Color | Black |
| Compatibility | Full compatibility with all of the various .300 AAC Blackout cartridges |
| Country Of Origin | USA |
| Generation | Gen M3 |
| Geometry | Constant-Curve Geometry |
| Grip Surface | Ribbed Gripping Surface |
| Label Panel | Paint Pen Dot Matrix Panel on Lower Label |
| Magazine Capacity | 20 Rounds |
| Model | MAG1182-BLK |
| Platform | AR-15 |
| Purpose | Purpose Built Magazine Only for .300 BLK |
| Spring | Long Life Stainless Steel Spring |
| Texture | Aggressive Front/Rear Texture |
| Visualtactical Differences | Designed With Visual and Tactical Differences |
Pros
- Purpose-built for .300 AAC Blackout cartridges in AR-15 pattern rifles
- 20-round capacity suits compact loadouts and controlled magazine management
- Visual and tactical differences help distinguish .300 BLK magazines quickly
- Gen M3 features and performance are carried over to this magazine
- Constant-curve geometry supports the magazine’s dedicated .300 BLK design
- Ribbed gripping surface and aggressive texture improve handling during reloads
Considerations & Trade-offs
- Purpose-built for .300 AAC Blackout, so it is not a general-purpose magazine for other AR-15 chamberings.
- The 20-round capacity is a deliberate trade-off versus higher-capacity options, which may matter for users wanting fewer reloads.
- Its visual and tactical differences are intended to help distinguish .300 BLK magazines, but that also means it is a specialized rather than universal setup.
- The product description emphasizes compatibility with a range of .300 AAC Blackout cartridges, but users should still keep magazine-to-ammunition pairing organized to avoid mix-ups.
Suggested Comparisons
- .300 AAC Blackout magazines
- AR-15 magazines
- Magazines for suppressed rifle setups
- Magazine accessories and storage
Suggested Accessories
- Magazine pouch
- Ammo storage box
- AR-15 cleaning kit
- Speed loader
Frequently Asked Questions
Is this magazine made for .300 AAC Blackout only, or can it be used with other AR-15 cartridges?
The product data identifies it as purpose-built for .300 AAC Blackout and says it is designed specifically for that cartridge. It does not state compatibility with other cartridges.
How many rounds does this magazine hold?
The listed capacity is 20 rounds.
Does the magazine have any visual differences to help distinguish it from other magazines?
Yes. The description says it was designed with visual and tactical differences so you can quickly identify your .300 BLK magazines.
What Gen M3 features are included?
The product data says it incorporates the same features and performance of the Gen M3 line, and it lists constant-curve geometry, a long-life stainless steel spring, ribbed gripping surface, aggressive front/rear texture, and a paint pen dot matrix panel on the lower label.
Is the country of origin provided?
Yes. The product data states Made in the USA.