Diamondback Firearms DB15USLB 5.56 NATO Semi-Auto Rifle, 16″ Barrel

Product Description

The Diamondback Firearms DB15USLB is a semi-auto rifle chambered in 5.56 NATO with a 16″ 4150 chrome moly barrel. It runs a direct impingement operating system with a carbine gas system, and it holds 30+1 rounds when loaded with a polymer AR-style magazine.

A few details set this rifle apart. The barrel is threaded and wears an A2 flash hider, so you have a starting point if you plan to change muzzle devices later. The twist rate is 1:8″, and the trigger is Mil-Spec. The rifle has a manual safety and no forward assist. The Black Anodized Hard Coat finish covers the metal, and the stock is a 6-position ATI Mil-Spec unit with A2-style grips. Overall length is 21.75″.

Who it suits

This rifle has no sights, so it fits a buyer who already knows how they want to set it up. If you like to pick your own optic or iron sights, this gives you a clean starting point. It also makes sense for a first AR build-out where you add parts over time.

Good pairings include a red dot or low-power optic, a set of flip-up backup sights, extra polymer AR-style magazines, a two-point or single-point sling, and a basic cleaning kit. A padded rifle case and a good set of ear and eye protection round out a range-ready kit.

Diamondback Firearms DB15USLB 5.56 NATO Semi-Auto Rifle, 16" Barrel Specifications

What’s in the Box

1 Magazine (per the manufacturer’s listing).

Fits and Pairs With

• Winchester Repeating Arms M193 5.56 NATO 55 gr Ammo, 150 Rounds
• PMC Ammunition M855 Green Tip 5.56 NATO 62 gr Ammo, 840 Rounds
• Winchester Repeating Arms M193 Full Metal Jacket 5.56 NATO, 200 Rounds
• Winchester Repeating Arms M855 5.56 NATO 62 gr Ammo, 200 Rounds

Ordering from Western Sport

Order online and we ship it to the licensed FFL dealer you choose near you — see how buying a gun online works. Western Sport has been a licensed FFL/SOT dealer since 2007, and everything we sell carries the full manufacturer warranty. Questions before you order? Send us a message.

Frequently Asked Questions

Q: What caliber is the Diamondback DB15USLB?

A: 5.56 NATO. It is a semi-auto rifle with a 16" barrel and a 30+1 round capacity.

Q: Does the Diamondback DB15USLB come with sights?

A: No. It has no sights, so you will need to add an optic, iron sights, or both.

Q: Is the DB15USLB direct impingement or piston?

A: Direct impingement. It uses a carbine gas system.

Q: What is the barrel twist rate on the DB15USLB?

A: 1:8". The barrel is 4150 chrome moly and 16" long.

Q: Does the DB15USLB have a forward assist?

A: No. This rifle does not have a forward assist. It does have a manual safety.

Warranty and Manufacturer

Covered by the Diamondback Firearms factory warranty; warranty terms come from Diamondback Firearms.

Additional information