Remington Model 51

The Remington Model 51 is a small pocket pistol designed by John Pedersen and manufactured by Remington Arms in the early 20th century for the American civilian market. Remington manufactured approximately 65,000 Model 51 pistols in .32 ACP and .380 ACP calibers from 1918 to 1927, though small numbers were assembled into the mid-1930s.

Development
John Pedersen designed or helped design many firearms for the Remington Arms Company. He had worked in concert with John Browning to design the Remington Model 17 which served as the basis for the Remington Model 31, Ithaca 37, Browning BPS, and Mossberg 500. He designed the Pedersen device that converted the M1903 Springfield into an autoloading intermediate-caliber weapon. Pedersen later worked for the US Army and provided competition to John Garand building an autoloading rifle to fire a full-power rifle cartridge. His design used lubricated cases and a toggle-bolt system much like the Luger pistol but eventually lost out to the M1 Garand.

Made in .380 ACP and later in .32 ACP caliber, it was marketed as a pocket pistol. While the European market embraced small-caliber pocket pistols, the American market favored revolvers. More expensive than the Browning-designed competition, the Model 51 was not much smaller. Furthermore, Remington was a company known for their long guns; their handguns had previously been limited to revolvers forced to play second fiddle to Colt in terms of sales.

Due to these factors, the Remington Model 51 enjoyed only limited commercial success. If competing with cheaper single-action blowback autoloaders made sales difficult, the stock market crash made sales nearly impossible. Impending autoloading pocket pistols like the Walther PPK ended any chance of further success by Remington pistols. For the smaller calibers it was made in, blowback operated pistols were cheaper, only slightly heavier, and did not produce excessive recoil. While the locking mechanism is still superior in many respects, the disadvantages in its complex trigger and safety mechanisms made the pistol difficult to sell. In many respects, the pistol came too early. In the 1980s and beyond, companies like Glock promoted their pistols' multiple, intuitive safety systems and advanced human engineering. These were both features Pedersen had pioneered over half a century prior.

General George S. Patton owned a Remington 51 and was thought to favor the weapon. Despite critical praise, no government or private agency is known to have adopted the weapon for use. Some examples are seen today with inventory numbers, however their origin is unknown. An anchor proof marking on some pistols has led to the mistaken belief that they were US Navy pistols bolstered by the fact that the Army did indeed recommend a .45-caliber version for adoption.

In the 1970s and 1980s, an inventor named Ross Rudd designed and prototyped a .45 ACP caliber pistol based on the Pedersen layout but with an inclined surface in place of the locking surface. This served to delay the opening of the breech rather than locking it. The pistol was planned for manufacture, but was never produced. The Italian firm Benelli produced limited numbers of B76, B80, and B82 pistols similar to the Rudd pistol however utilizing a lever-delayed blowback system.

Design details
The layout of the Remington 51 is similar to the Walther PPK pistol in the use of a stationary barrel and recoil spring surrounding the barrel. However, the unique feature is the use of a locking breech block within the slide. 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, and the continuing 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 lugs. Only manually retracting the slide or firing a cartridge opens the gun. The Remington Model 51 was the only production pistol to utilize Pedersen's type of operating system.

Because the breech is locked, this pistol can handle greater pressures than a blowback firearm yet without the size and weight penalty of other locking systems. The design also allows the recoil spring to be placed around the barrel making for a shorter profile gun. Lighter operating parts and longer lock time provide less felt and actual recoil. A lower bore axis gives less muzzle rise which also lowers felt recoil. A fixed barrel allows for greater accuracy and reliability as well as simplifying construction compared to other locking systems. Overall, this system is lighter than a blowback, simpler than any conventional locking mechanism, and has less recoil than either of the other systems.

The Remington Model 51 uses an internal hammer and features a single-action trigger. A unique combination lever on the rear of the grip-frame acts as a safety, bolt hold-open device and bolt release. This is in addition to the grip safety, magazine safety disconnect, and relatively heavy trigger pull. The grips are held on with spring-tensioned studs rather than screws. Not a single screw is used in the entire pistol. Pedersen was greatly concerned with human engineering and developing a comfortable grip angle for his pistol while not sacrificing the slim profile. Field stripping the pistol is cumbersome but not overly complicated.

Variants
Despite its shortcomings, the design was recommended for adoption by the Army Board during the First World War as the scaled-up .45 caliber Remington Model 53. Testing of the prototype against production M1911 showed the Remington design to be more reliable. Initially, Remington demanded a large amount of money up-front to tool-up for the gun, but negotiations were cut short by America's entrance into World War I. Available factories were tooled to produce the M1911 so investment in ramping-up production for another pistol did not make sense. Production of the 1911 kept pace with wartime demands and Remington itself was eventually contracted to produce the Colt weapon.

Because of a lower bore axis, lighter slide, and locked breech, the Remington 53 boasted much less felt recoil than the M1911. This fact was attested to by noted firearms expert Julian Hatcher. The Remington pistol was also more accurate, lighter, and had fewer moving parts than the 1911. Despite its advantages over the M1911, there was too little civilian market to support a large-bore pistol at that time, a military contract was now unlikely, and the M1911 already had a firm foothold. Remington abandoned the larger pistol and focused on the Model 51.