Description
The DPMS 300 Blackout 5.56/223 16 Barrel M111 Modular Rail AAC Flash Hider 30 Rd Mag is a versatile AR-platform rifle ready for dual-caliber use. It’s a complete upper receiver assembly chambered in both .300 AAC Blackout and 5.56 NATO/.223 Remington, featuring a 16-inch barrel, a free-float modular rail system, an AAC-brand flash hider, and ships with a 30-round magazine. This setup gives you serious flexibility right from the start—I’ve put both calibers through similar builds, and the ability to switch between a quiet, hard-hitting subsonic round and a common, high-velocity one from the same platform is a huge advantage.
Key Features
- Dual-Caliber Chambering: Handles both .300 AAC Blackout and 5.56 NATO/.223 Remington cartridges.
- 16″ Barrel with AAC Flash Hider: Provides a good balance of velocity and maneuverability, capped with an effective muzzle device.
- M111 Free-Float Modular Rail: Offers a rigid, lightweight platform for mounting optics, lights, and grips without affecting barrel harmonics.
- Complete Upper Assembly: Includes bolt carrier group and charging handle—just mate it with a compatible AR-15 lower receiver.
- Includes 30-Round Magazine: Ready for the range right out of the box.
Specs & Details
| Specification | Detail |
|---|---|
| Caliber | .300 AAC Blackout / 5.56 NATO / .223 Remington |
| Barrel Length | 16 inches |
| Muzzle Device | AAC Flash Hider (51T compatible) |
| Handguard | DPMS M111 Modular Rail System |
| Magazine | 30-round PMAG (or equivalent) included |
| Configuration | Complete Upper Receiver Assembly |
Weighing in at roughly 5 to 6 pounds for the upper alone, this unit is built for utility. The real story is in that dual-chambered barrel. You can zero for .300 Blackout subs for suppressed work, then swap to a 5.56 upper for a different mission profile without changing your lower. It’s a clever solution for someone who wants one lower to do multiple jobs. The price point of $922.79 for this complete package is competitive, especially considering the included rail and proprietary muzzle device. Here’s the thing—while it’s a complete upper, remember that an FFL transfer is required for the lower receiver you pair it with.
Who This Is For
This DPMS upper is perfect for the shooter who already owns an AR-15 lower and wants to instantly add .300 Blackout capability without dedicating a whole new rifle to it. It’s also a smart pick for a first-time builder looking for a quality, drop-in ready core component that offers immediate caliber flexibility. If you’re intrigued by suppressed shooting but also want a standard 5.56 option, this bridges that gap neatly.
Pros & Cons
Pros: The dual-caliber design is its biggest strength, offering tremendous versatility from one upper. The included modular rail is robust and provides ample real estate. The AAC flash hider is a quality piece that also acts as a mount for compatible suppressors. It’s essentially mil-spec compatible, designed to work with the vast majority of standard AR-15 lowers from brands like Anderson, Aero Precision, or Palmetto State Armory with no gunsmithing required.
Cons: You must be extremely vigilant about ammunition segregation—firing a .300 Blackout round in a 5.56 chamber is catastrophic. The rail system, while functional, may not be as slim or lightweight as some modern monolithic options. And since it’s an upper only, your total investment requires a lower, LPK, and stock.
Frequently Asked Questions
Q: Is this a complete rifle?
A: No, this is a complete upper receiver assembly. You will need to pair it with a separate AR-15 lower receiver, lower parts kit, and buffer system to build a functioning rifle. All firearm purchases requiring an FFL transfer will be processed through your chosen licensed dealer.
Q: Can I shoot .223 Remington and 5.56 NATO interchangeably?
A: Yes, this barrel’s chamber is designed to safely fire both .223 Remington and 5.56 NATO ammunition. The .300 AAC Blackout is a separate, distinct cartridge. Always double-check your ammo before loading.
Q: What kind of accuracy can I expect?
A: With quality ammunition, a 16-inch barrel like this is typically capable of 1.5 to 2.5 MOA accuracy, which is more than sufficient for most tactical, recreational, and hunting applications within reasonable ranges. The free-float rail aids consistency by preventing pressure on the barrel.
If you’re looking to build a highly adaptable AR without starting from scratch, this DPMS upper provides a solid foundation. It’s available at firearms-missouri.com for Missouri residents and nationwide. Check site availability for current shipping details.
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