This is the most common complete upper length sold in 300 Blackout, and for good reason. At 10.5 inches you get essentially all the velocity the cartridge offers, a longer handguard than a 9 inch build, and a package that still handles well indoors with a suppressor fitted.
| Component | Specification |
|---|---|
| Chambering | 300 AAC Blackout |
| Barrel | 10.5 inches, 1:7 twist |
| Platform | AR-15, barrel swap only |
| Buffer | H2, adjustable gas block |
| Defensive load | 110gr to 125gr expanding supersonic |
| Velocity | roughly 2,250 fps with 110gr |
| Muzzle energy | roughly 1,235 ft lbs |
| Intended use | home defense, truck gun, short range hunting |
The case for this build over a 10.5 inch 5.56 is muzzle blast. 5.56 loses a great deal of velocity from a short barrel and produces enormous flash and concussion doing it. 300 Blackout was designed for exactly this length, so it burns its powder inside the barrel rather than in front of your face.
Choose the load deliberately. Full metal jacket practice ammunition is not a defensive load at any barrel length. Our home defense load guide covers what expands at short barrel speeds, the ballistics chart lists velocity by barrel length, and the 300 Blackout ammo shelf carries the options.
