The Diamondback DBX57 CF is a semi-automatic pistol chambered in 5.7x28mm. It has an 8-inch stainless steel barrel, 7075-T6 aluminum receiver in dark grey, M-Lok handguards, and Magpul MOE K grips. Capacity is 20+1 rounds, weight is 3 lbs, and overall length is 16 inches. No iron sights are included; the top rail is optics-ready. Trigger is mil-spec. 
 

Key Specifications 

• Brand: Diamondback 
• Model: DBX57 CF 
• Caliber: 5.7x28mm 
• Action: Semi-Automatic 
• Capacity: 20+1 rounds 
• Barrel Length: 8 inches 
• Overall Length: 16 inches 
• Weight: 3 lbs 
• Receiver Material: 7075-T6 Aluminum 
• Finish Color: Dark Grey 
   

Detailed Features 

At 3 lbs the DBX57 CF is light for a pistol with an 8-inch barrel. The 7075-T6 aluminum receiver is the same alloy used in AR-platform lowers -- strong for its weight. M-Lok handguard positions allow light, foregrip, or other accessories without proprietary adapters. The optics-ready top rail accepts most red dots and low-power variables directly. 5.7x28mm produces high velocity with low felt recoil compared to pistol-caliber alternatives, which makes it manageable for fast follow-up shots from a 20-round magazine. 
 

Usage Scenarios 

• Home Defense: 20+1 rounds of 5.7x28mm with a light and optic is a capable defensive setup. The low recoil makes the platform controllable for a wide range of shooters. 
• Competitive Shooting: Light weight and optics-ready configuration suits run-and-gun formats. 
• Range / Training: 5.7x28mm has less recoil than 9mm carbine-length options and the 20-round capacity means fewer reloads per string.

Owners of the Diamondback DBX57 CF in 5.7x28mm tend to focus on a few consistent themes.

The caliber draws most of the initial interest. 5.7x28mm is high-velocity with low recoil, and owners who switch from 9mm pistol-caliber carbines often note the difference in felt recoil during rapid fire. The 20+1 capacity adds to the appeal for range use.

The lightweight build is well-received. At 3 lbs before an optic, it's light for the format, and the aluminum receiver holds up to regular use without issues most owners report.

Reliability gets mixed feedback. Many owners run it without problems across a range of 5.7x28mm loads. A subset reports occasional feeding or extraction issues, particularly with certain ammunition types or early in break-in. The 5.7x28mm ammunition ecosystem is narrower than 9mm, which means not all loads cycle equally well.

The optics-ready design is practical. No iron sights means buyers need to add an optic on day one, which adds cost but also means no height-over-bore compromise from iron sights under a red dot.

Aftermarket support is thinner than for established platforms. Holsters in particular require more searching, and some accessories require Diamondback-specific sourcing.

Price comparisons come up often. The DBX57 CF is positioned against FN Five-seveN and PS90 platforms, and buyers who research that comparison usually arrive with clear expectations about what they're getting.