Diamondback DB15 300 Aac Blackout 16 Barrel 30 Rounds

About this product

The Diamondback DB15 is an AR-15 pattern semi-automatic rifle chambered in .300 AAC Blackout, built with a 16-inch heavy-contour, black-nitride-finished barrel and forged 7075-T6 aluminum upper and lower receivers on an A3 flattop configuration. Diamondback lists several DB15 .300 Blackout SKUs at different price points depending on finish and furniture, and the price here reflects the plain black configuration matching this listing.

What does .300 Blackout offer over a standard 5.56/.223 AR-15?

.300 Blackout was designed to deliver significantly more energy at the muzzle and downrange than 5.56 NATO out of shorter barrels, while running reliably both suppressed and unsuppressed and cycling in subsonic and supersonic loadings from the same rifle. This DB15 uses a pistol-length gas system tuned specifically for the cartridge, a 1:8 twist rate suited to the range of bullet weights .300 Blackout is loaded in, and an A2-style .30-caliber flash hider on a 5/8x24 thread pattern.

What's included on this configuration?

This build uses a 12-inch KeyMod handguard, a Magpul MOE six-position collapsible stock, and a Magpul MOE pistol grip, with a 30-round Magpul PMAG (Gen 3, .300 Blackout-marked) as the factory magazine. At 6.62 pounds and a 32.25-to-35.5-inch collapsed-to-extended overall length, it's a standard-weight, duty-style AR-15 pattern carbine rather than a lightweight or heavy-barrel variant.

Does this rifle, as configured, meet California requirements?

Not as shown, in most respects that matter under state law. California's assault weapon statute restricts semi-automatic centerfire rifles with a detachable magazine when combined with certain features, including a protruding pistol grip like the Magpul MOE grip on this build, and California separately caps detachable magazines at 10 rounds — well under the 30-round PMAG this rifle ships with. Buying this specific configuration for use in California would require a featureless or fixed-magazine build and compliant, reduced-capacity magazines. Confirm exact current requirements, and whether this rifle can be legally configured to meet them, with your FFL or a knowledgeable gunsmith before ordering — do not assume any AR-15 pattern rifle can simply be carried across state lines and used as configured.

How does delivery work?

As a complete rifle, the DB15 ships to a licensed FFL dealer for pickup, not to your home address, where you'll complete a background check and the standard transfer paperwork, the same as for any other long gun.

Outside of California-specific configuration questions, the DB15 platform is a straightforward, mil-spec-pattern AR-15 built by an established American manufacturer, using widely available AR-15 furniture, magazines, and aftermarket parts across the broader platform. Diamondback's use of forged 7075-T6 receivers and a chrome-moly barrel with a black nitride finish are standard, proven material choices for a duty-grade AR-15 rather than budget stampings, and .300 Blackout's compatibility with standard AR-15 magazines and lowers (only the barrel, bolt, and magazine markings differ from a 5.56 build) makes ammunition and parts support broadly accessible outside states with additional configuration requirements.

For a buyer outside a restrictive state, this configuration works well as either a home-defense carbine or a suppressed range and hunting gun, since .300 Blackout was specifically engineered to perform well through a can without the drastic velocity loss some cartridges suffer from shorter, suppressor-hosted barrel lengths. The 16-inch barrel length keeps this particular DB15 outside the short-barreled-rifle category that would otherwise require NFA paperwork, which is worth noting for buyers newer to the platform who might be considering a shorter barrel later — going under 16 inches on a rifle-configured lower brings a different, more involved regulatory process into play. As with any AR-15 pattern rifle, routine maintenance is straightforward with standard AR-15 tools and widely available cleaning kits, and Diamondback backs its rifles with the kind of parts and warranty support expected from an established, dedicated AR-15 manufacturer.