The Ruger 57 is a full-size semi-automatic pistol chambered in 5.7x28mm with a 4.9-inch barrel, 20-round magazine capacity, and a Cobalt Blue Cerakote finish. The polymer frame keeps weight at 24.5 oz. unloaded. 
 

Key Specifications 

• Manufacturer: Ruger 
• Model: 57 
• Caliber: 5.7 x 28mm 
• Barrel Length: 4.9 inches 
• Capacity: 20 rounds (plus one in chamber) 
• Weight: 24.5 oz. 
• Finish Color: Cobalt Blue Cerakote 
• Frame Material: Polymer 
• Action Type: Semi-Automatic (Double Action) 
• Sights: Fiber optic front sight & adjustable rear sight 
   

Detailed Features 

 
The 5.7x28mm caliber is the defining characteristic here. It's a bottlenecked pistol cartridge originally developed for the FN P90 — high velocity, flat trajectory, and low recoil relative to its energy level. The Ruger 57 is one of the more accessible platforms chambered for it. The alloy steel barrel has a black nitride finish for corrosion and wear resistance. The Secure Action fire-control system uses a protected internal hammer with a bladed-safety trigger — short pull, clean break. Disassembly is tool-free and does not require pulling the trigger. The fiber optic front sight and adjustable rear sight work well for precision shooting. The textured polymer grip is ergonomic and handles well at 24.5 oz. 
 

Usage 

 
The Ruger 57 is used for competitive shooting, range practice, and home defense. The 20-round capacity and low felt recoil from the 5.7x28mm make it practical for extended shooting sessions. The Cobalt Blue Cerakote finish is a limited aesthetic variant of the standard configuration.

The Ruger 57 in Cobalt attracts a lot of discussion, mainly because the 5.7x28mm caliber itself is polarizing — people either find it compelling or dismiss it as a niche round.

The most consistently praised aspects are the caliber's ballistics and the pistol's feel in the hand. The 5.7mm round has notably low recoil for its velocity, which makes extended range sessions comfortable and follow-up shots fast. The 20-round capacity gets steady positive mentions — it's more than double most common pistol magazines and changes the character of range shooting. The fiber optic sights are called out as practical and easy to pick up quickly.

Amunition cost and availability are the main practical concerns. 5.7x28mm costs more per round than 9mm and has fewer sources, which matters for owners who shoot frequently. Some owners have reported occasional malfunctions with certain ammunition brands, though most report reliable function with quality loads.

Price of the pistol itself generates some debate. Some buyers view it as fair for what it offers; others compare it to 9mm full-size pistols at lower price points and find the value argument less clear unless they're specifically committed to the 5.7mm caliber.

The Cobalt Blue finish gets positive aesthetic comments — it's different from the standard black configuration and appeals to buyers who want something visually distinct. Build quality is generally praised without major complaints about materials or fit.

Overall, the Ruger 57 Cobalt has a dedicated following among shooters who want the 5.7x28mm experience in a domestically-made platform, tempered by the practical reality of feeding a less common caliber.