Diamondback Firearms DB1984K061 DB15 Obsidian 5.56 NATO 11.5" 31-Round

The Diamondback Firearms DB1984K061 DB15 Obsidian 5.56 NATO 11.5" rifle is a purpose-built short-barrel platform designed for close-quarters combat, breaching operations, and tactical applications where maneuverability outweighs extended-range engagement. With its compact 11.5-inch barrel and full 31-round magazine capacity, this rifle excels in confined spaces—whether vehicle compartments, building entries, or defensive home scenarios—without sacrificing the velocity and terminal ballistics that 5.56 NATO delivers. Law enforcement and military units deploy similar configurations for their ergonomic handling and rapid target transitions in high-stress environments.

The Obsidian variant incorporates a free-floating barrel and optimized gas tube tuning to ensure reliable function despite the shortened gas column that short-barrel rifles typically encounter. At 7.7 pounds, the rifle balances weight savings with structural rigidity, critical when sustained fire or rapid handling is demanded. The 11.5-inch tube generates approximately 2,700–2,800 foot-per-second muzzle velocity with 5.56 NATO ammunition, producing sufficient energy for intermediate distances while suppressing muzzle signature and blast signature—attributes valued in tactical operations where hearing protection and situational awareness matter equally.

Operators, armorer-level shooters, and civilian tactical practitioners benefit most from this configuration. The 31-round magazine feeds reliably across duty and commercial ammunition lots, and the Diamondback platform accepts standard AR-15 upper receiver components, enabling customization for optics, suppressors (with appropriate threading), and rail-mounted accessories. Before purchasing, verify local and state regulations regarding short-barrel rifles, as barrel length restrictions vary by jurisdiction and may require federal registration or licensing.