What “Diamondback 5.56 16″ M-LOK” Means

This description is a shorthand often used to describe attributes of a rifle or rifle upper assembly, particularly in the AR-15 style platform:

“Diamondback”

• Likely refers to Diamondback Firearms, a U.S. company that produces rifles and pistols.

“5.56”

• Short for 5.56×45 mm NATO, a common rifle cartridge caliber used in many military and civilian rifles.

 “16″”

• Indicates a 16-inch barrel length. In many jurisdictions (including the U.S.), a rifle barrel of at least 16″ classifies it as a rifle instead of a short-barreled rifle (SBR) for regulatory purposes.

 “M-LOK”

• Refers to a modular accessory mounting system developed by Magpul. M-LOK slots on the handguard allow attaching lights, grips, rails, and other accessories without Picatinny rail sections everywhere.

General Description (Technical Specs)

• Platform: Diamondback DB15 (AR-15 style semi-automatic)

• Caliber: 5.56×45 mm NATO (.223)

• Barrel Length: 16 inches (standard rifle length in many jurisdictions)

• Twist Rate: Typically 1:8 RH (common for 5.56 NATO barrels)

• Gas System: Mid-length or carbine-length depending on sub-variant

• Handguard: ~15 inch M-LOK rail (attachment slots for accessories)

• Sights: “N/S” means no sights included — the upper comes without iron sights or optic installed.

• Finish (BL): Black finish overall (often black nitride or hardcoat anodize)

• Receiver Material: Forged 7075-T6 aluminum upper and lower

• Bolt Carrier Group: Mil-Spec shot-peened, MPI-inspected with 8620 carrier

Typical Features You’ll Find on These

• Magpul-style Grip and Adjustable Stock (varies by package)

• 15-Round (or 30-Round) Magazine Compatibility (standard AR-15 pattern)

• Muzzle Device: A2 flash hider or similar depending on exact variant

• Weight: ~6.6–6.8 lbs unloaded on comparable builds

• Length: ~32.5 – 36.75 inches overall depending on stock position