Remington Model 51
The Remington Model 51 is a compact semi-automatic pocket pistol designed by John D. Pedersen and produced by Remington Arms Company from 1918 to 1927, chambered primarily in .380 ACP with a secondary variant in .32 ACP, featuring a unique hesitation lock mechanism for reliable operation in a slim, ergonomic frame that holds seven rounds in the magazine plus one in the chamber.[1][2][3] Introduced near the end of World War I for civilian self-defense and concealed carry, the Model 51 represented an innovative departure from traditional blowback designs through its delayed blowback system, which utilized a separate breechblock and slide assembly to mitigate recoil while maintaining a lightweight profile of approximately 21 ounces unloaded.[2][4][3] Its ergonomic "self-aiming" grip, low bore axis, and art deco-inspired aesthetics made it a premium choice for the era, though its complexity and higher cost—often two to three times that of comparable revolvers—limited broader adoption despite strong sales of around 65,000 units, with 54,518 in .380 ACP and 10,278 in .32 ACP.[1][5][4] The pistol incorporated multiple safety features, including a grip safety, thumb safety, and magazine disconnect, alongside a fixed barrel and snag-free controls for ease of carry, but its intricate field-stripping process and sensitivity to ammunition quality contributed to its discontinuation in 1927, after which a small number of units were assembled from remaining parts into the 1930s.[2][3][4] Today, the Model 51 is prized by collectors for its historical significance in early 20th-century handgun development and Pedersen's engineering legacy, which also influenced designs like the Pedersen Device for military rifles.[4][5]Development
Designer John Pedersen
John Douglas Pedersen (May 21, 1881–May 23, 1951) was an American firearms designer born in Grand Island, Nebraska, to Danish immigrant parents who settled in Wyoming.[6] In 1907, he joined Remington Arms Company as a consulting engineer, where he quickly established himself as a prolific innovator in firearm mechanisms, contributing to numerous successful designs including rifles, shotguns, and pistols over his three-decade tenure.[7] Pedersen's expertise stemmed from his self-taught engineering skills and hands-on approach, earning him over 60 U.S. patents and recognition from contemporaries like John Moses Browning as one of the foremost gun designers of his era.[8] Pedersen began work on the Remington Model 51 in 1913, envisioning a compact, reliable semi-automatic pocket pistol suitable for civilian self-defense.[9] He filed the foundational patent application on July 30, 1915, which was granted as U.S. Patent 1,348,733 on August 3, 1920, covering the core design elements of the pistol.[9][10] During World War I, Pedersen's motivation extended to potential military applications, leading him to adapt the design into the .45 ACP-chambered Model 53 in 1917 for evaluation as a compact sidearm, though no production contract materialized amid the war's demands on Remington's facilities.[3] Following the Armistice of November 11, 1918, Pedersen played a pivotal role in Remington's pivot from wartime rifle and ammunition production to commercial firearms, overseeing the refinement and launch of the Model 51 for civilian markets starting in September 1919.[9] This transition capitalized on Pedersen's pre-war prototypes, with the pistol entering full production and incorporating subsequent patents—such as those filed between 1921 and 1926 for ergonomic and functional enhancements—to meet post-war demand for personal protection handguns.[3] Over the next seven years, 64,796 units were manufactured before discontinuation in 1927, reflecting Pedersen's influence in adapting military-derived innovations for peacetime use.[9]Historical Context and Production
Following the Armistice of November 11, 1918, which ended World War I, Remington Arms transitioned its manufacturing efforts from military contracts—primarily the production of 545,541 U.S. Rifle, Caliber .30, Model of 1917 Enfield rifles (of the total ~2.2 million across all manufacturers) at its Ilion, New York facility—to civilian firearms as wartime demand evaporated.[11] This shift allowed Remington to repurpose machinery previously dedicated to military output for new consumer products, including semi-automatic pistols designed for personal defense.[9] The Remington Model 51 was first announced in late 1918 as part of this postwar pivot, with full-scale production beginning in September 1919 at the Ilion plant.[12] Initially chambered exclusively in .380 ACP, the pistol entered the civilian market at a retail price of $36.30, positioning it as a premium option for concealed carry among law-abiding citizens seeking reliable self-defense tools.[13] In August 1921, a .32 ACP variant was introduced to broaden appeal, though it represented a smaller portion of output.[12] Over its production run from 1919 to 1927, Remington manufactured 64,796 Model 51 pistols, with 54,518 chambered in .380 ACP and 10,278 in .32 ACP.[13] Despite promotional efforts highlighting its ergonomic "self-aiming" design, the model's intricate hesitation-lock mechanism drove up production costs, making it less competitive against simpler, lower-priced alternatives like the Colt Pocket Model 1903.[12] These economic pressures, compounded by a saturated pocket pistol market, led to discontinuation on August 18, 1926, after which remaining parts were assembled sporadically into the early 1930s.[13]Design and Features
Operating Mechanism
The Remington Model 51 utilizes a delayed blowback system, often termed a hesitation lock, invented by John Pedersen, which incorporates a skeletonized floating breechblock housed within the slide. This breechblock initially moves rearward with the slide upon recoil but is delayed in unlocking by an impinging shoulder or cam surface against the frame, ensuring that chamber pressure drops to a safe level before full extraction occurs—typically after the slide travels approximately 0.083 inches and the breechblock lifts or tilts to disengage.[3][14][1] In operation, the pistol functions in single-action mode with an internal hammer that strikes a firing pin mounted in the breechblock to detonate the cartridge primer. Recoil from the fixed-barrel design drives the slide and breechblock rearward together for a short distance (about 2 mm for the bolt head), at which point the breechblock hesitates while the slide continues (up to 5 mm), allowing gas pressure to equalize; the extractor then removes the spent case, which is ejected through the port, and the recoil spring returns the slide forward to strip and chamber a fresh round from the detachable box magazine. The system supports .32 ACP or .380 ACP calibers, with magazine capacities of 8 rounds for the former and 7 for the latter.[3][14][1][15] For user safety, particularly in a pocket carry pistol, the Model 51 integrates a grip safety on the backstrap that locks the sear, disconnector, and slide unless depressed by the shooter's hand, visually indicating when the hammer is cocked. A manual thumb safety on the left frame side further secures the action by blocking the grip safety and hammer when applied, while a magazine safety prevents firing if the magazine is removed. These features collectively enhance safe handling without compromising accessibility.[3][16][15] The delayed blowback design offers advantages over simple blowback systems, including reduced felt recoil through momentum transfer via the floating breechblock, enabling a lighter slide mass for improved control and accuracy during rapid fire. However, the precision machining of the breechblock's angled abutments, slide recesses, and cam interfaces—angled below the friction threshold to ensure reliable delayed unlocking—resulted in elevated manufacturing costs and complexity.[3][14][1] Field disassembly for cleaning requires no tools: first, unload and remove the magazine to engage the magazine safety; cock the slide fully to align a half-moon cutout in the barrel extension with the retaining pin; withdraw the pin, allowing the barrel, breechblock, and slide to be removed as a unit; then separate the barrel and breechblock by tilting the latter upward, with the firing pin and spring detaching freely. Reassembly follows in reverse.[3][15][16]Physical Specifications
The Remington Model 51 pistol measures 6.6 inches in overall length, with a barrel length of 3.5 inches, a height of 4.1 inches, and a width of approximately 0.9 inches, making it notably compact for its era.[17][2] Its unloaded weight is 21 ounces, contributing to its lightweight profile suitable for everyday carry.[1][17] The pistol was primarily chambered in .380 ACP with a magazine capacity of 7 rounds plus one in the chamber, while the .32 ACP variant offered 8 rounds plus one, requiring an adjusted recoil spring for the smaller caliber.[1] It features a blued steel frame and slide for durability and corrosion resistance, paired with checkered black plastic grips that provide a secure hold without adding bulk.[2] Sights consist of a fixed blade front and square-notch rear, optimized for close-range accuracy, while controls include a heel-mounted magazine release, a grip safety, and a thumb-operated manual safety, but no slide lock for simplicity in operation.[1][2] Ergonomically, the Model 51 emphasizes concealed carry with its slim, snag-free design featuring rounded edges, a natural-pointing grip angle, and a low bore axis to reduce muzzle flip during firing.[2][4] This configuration, enabled by its delayed blowback mechanism, balances portability and controllability.[1]| Specification | .380 ACP Variant | .32 ACP Variant |
|---|---|---|
| Magazine Capacity | 7 rounds | 8 rounds |
| Overall Length | 6.6 inches | 6.6 inches |
| Barrel Length | 3.5 inches | 3.5 inches |
| Weight (Unloaded) | 21 ounces | 21 ounces |