The Remington R51 is a subcompact 9mm +P pistol with a 3.4-inch barrel, 7+1 capacity, and an aluminum alloy frame with black hardcoat anodized finish. It weighs 22.6 oz and uses a grip safety as its primary safety mechanism. 
 

Key Specifications 

• Manufacturer: Remington 
• Model: R51 
• Series: SubCompact 
• Caliber: 9mm Luger +P 
• Action: Single 
• Barrel Length: 3.4 inches 
• Overall Length: 6.68 inches 
• Overall Height: 4.63 inches 
• Weight: 22.6 ounces (1.4 pounds) 
• Capacity Standard: 7+1 rounds 
• Frame Material: Aluminum Alloy 
• Frame Finish: Black Hardcoat Anodized 
• Safety Type: Grip safety 
• Sights Front/Rear: FT: 1-Dot, RR: 2-Dot 
   

Features 

The R51 uses a Pedersen-type hesitation-locked action rather than a traditional Browning tilting-barrel design — the aluminum alloy frame houses a separate locking block that delays the slide while pressure drops to a safe level. The grip safety prevents discharge unless the pistol is properly held. The hardcoat anodized finish on the aluminum frame handles corrosion and moderate wear. The polymer grip fits within the subcompact footprint for carry. 
 

Who It's For 

The R51 suits shooters who want a subcompact 9mm +P-rated pistol in an aluminum-frame package. The grip safety is either a feature or a concern depending on personal carry preferences.

The R51 has a complicated reputation driven largely by documented reliability problems at launch.

The design concept gets genuine appreciation from shooters who understand the Pedersen action — the hesitation lock is mechanically interesting and the grip safety addresses certain carry safety concerns. The compact aluminum frame is well-regarded for feel and weight. Ergonomics get positive marks from most owners who've shot a functioning example.

The reliability issues from the release are the dominant topic. Failures to feed and eject were reported widely enough that Remington issued a recall and redesigned the pistol as Gen 2. Buyers discussing the specifically are divided between those who've had smooth experiences and those who haven't. This uncertainty around reliability makes many potential buyers cautious regardless of the pistol's other attributes.

Aftermarket support is limited compared to Glock, M&P, and similar platforms. The R51's value proposition is primarily the design and the grip safety; shooters who don't need those specifically will find comparable or more proven alternatives for the same money.