Remington R51

The Remington R51 is a semi-automatic pistol announced in January 2014. The R51 is a modernized version of the John Pedersen-designed Remington Model 51 pistol chambered in 9×19mm caliber. The company plans to offer the pistol in .40 S&W and other calibers in future.

Design details
The layout of the Remington R51 is similar to the Walther PPK pistol in the use of a stationary barrel and recoil spring surrounding the barrel. However, the notable feature is the use of a locking breech block within the slide utilizing the "hesitation-locked" action originally developed by John Pedersen. When the pistol is in battery, the breech block rests slightly forward of the locking shoulder in the frame. When the cartridge is fired, the bolt and slide move together a short distance rearward powered by the energy of the cartridge as in a standard blowback system. When the breech block contacts the locking shoulder, it stops, locking the breech. The slide continues rearward with the momentum it acquired in the initial phase. This allows chamber pressure to drop to safe levels while the breech is locked and the cartridge slightly extracted. Once the bullet leaves the barrel and pressure drops, the rearward motion of the slide lifts the breech block from its locking recess through a cam arrangement, continuing the operating cycle. One can insert a dowel into the barrel and push on the breech block. It will only move a fraction of an inch and stop against the recoil shoulder. Only manually retracting the slide or firing a cartridge opens the pistol.

Because the action halts cartridge extraction momentarily, the R51 can use higher pressure cartridges than a straight blowback firearm with similar slide weight. The hesitation-locked Model 53 was based on the Model 51 design, and was built by Remington in .45 ACP for Navy trials. The Pedersen design has the recoil spring surrounding the barrel, reducing the pistol's overall profile. Lighter operating parts and longer lock time provide less felt and actual recoil. The R51's low bore axis gives less muzzle rise which also lowers perceived recoil, while the stationary barrel improves accuracy and simplifies construction.

The Remington R51 uses an internal hammer with a built-in drop safety and features a single-action trigger. The slide stop is mostly recessed into the left side of the frame. The primary safety is a grip safety which must be depressed before the pistol will fire. The R51 lacks the magazine safety that was present on the original model 51. The trigger guard is undercut to allow a higher grip on the frame. The frame has a 20-degree grip angle designed for natural point shooting, and has checkering on the front strap for improved purchase on the gun. The R51 comes standard with polymer grip panels which are held on with conventional screws. Remington plans to offer optional rubber and rosewood grip panels as accessories for users desiring a wider, more hand-filling grip. The magazine is a steel single-column design with a polymer floorplate. Capacity is 7 rounds in 9×19mm. The magazine release is ambidextrous. The slide of the R51 is machined from stainless steel and has a matte black FNC finish, while the frame is machined from 7075 aluminum alloy and has a matte black anodized finish  The 3.4" barrel is machined from 416 stainless steel and has a bright finish.

Production problems
A press release from Remington in July 2014 said that production of the R51 had been suspended and was expected to resume in October. Customers had informed Remington "that some R51 pistols had performance issues". Remington determined that these "performance problems resulted from complications during our transition from prototype to mass production." Although the pistol appeared at SHOT 2015, as of SHOT 2016 all mention of the R51 has been removed from both the web site and catalogs. No new Remington R51s are shipping, nor has Remington announced a production and shipping schedule for the R51.