Remington Model 51
The John D. Pedersen designed Remington Model 51 was the commercial adaptation of the earlier .45 ACP Model 53 (or Model 1917) developed for military service. Offered first to the US Army who were willing to test the new pistol but continued to place orders for M1911s. Remington decided not to provide a pistol for tests. However, in April 1918 the US Navy requested a pistol to test as they had struggled to get enough M1911′s to adequately equip both the Navy and Marine Corps as the Army had priority.
Remington provided a Model 53 for a battery of tests carried out in June 1918. Following a 5,000 round endurance test, sand test and a evaluation against the M1911 and a Grant-Hammond Pistol the Navy testing board found that the Model 53 was “…a simple, rugged and entirely dependable weapon, which should be suitable in every respect for a service pistol.” However, the high unit cost quoted for the pistol by Remington undermined its adoption by the Navy. With the war in Europe about to end the Navy decided to abandon the project.
The Remington Model 53 (source)
With peace approaching and large-scale military contracts about to dry up Remington saw Pedersen’s pistol as a possible commercial success. They developed smaller versions in the popular .32 ACP and .380 ACP calibres and in August 1920 Pedersen was granted a very detailed patent (originally filed in 1915) protecting all elements of his design. Pedersen and another Remington designer Crawford C. Loomis filled further patents in 1919 and 1920.
Remington introduced the Model 51 onto the civilian market in .380 ACP in late 1918 with full production beginning in 1919. Unlike the Model 53, tested by the Navy, the Model 51 had a concealed hammer and thumb and grip safeties but did not have the Model 53′s slide lock. Production of the .32 ACP model began in 1921 and production continued until 1927, with some pistols assembled from parts into the early 1930s. Remington made approximately 65,000 Model 51s before production ended.
Patent drawing detailing Pedersen’s hesitation lock (source)
Pedersen’s pistols had a unique action, developed to sidestep John Browning’s patents to avoid infringement. He achieved this by devising a system which had a separate slide and breechblock. Once the pistol was fired the slide and breechblock recoiled together for a short distance of approximately 5mm before the breechblock locked against a lug in the pistol’s frame. The slide continued to the rear with the breechblock travelling on a cam track up, out of the locked position. The slide and breechblock then continued together the full length of travel. The result is what is sometimes described as a hesitation lock. Remington sales brochures claimed that the pistol’s “breech remains positively locked until bullet has left the muzzle – not a blowback action.”
The Pedersen is an ergonomic pistol with a comfortably angled grip and low bore-axis. It points naturally and despite its heavy trigger it is an accurate pistol. The Model 51 has three safeties, a grip safety, manual safety and a magazine disconnect. The manual safety is located just behind the left-side grip panel and appears to have been an afterthought as Pedersen’s patent does not include it. Unlike many contemporary pocket automatics it has a thumb-operated magazine release rather than the heel release used by the Colt Pocket Hammerless and FN Model 1910. The .32 ACP Model 51 could hold 8-rounds in its single stack magazine while the .380 ACP version could hold 7-rounds.
In an effort to increase their sales Remington priced the Model 51 at $15.75, cheaper than Colt’s $20.50 Pocket Model. Despite this Colt retained market dominance in the US and the price cut combined with the Model 51′s expensive manufacturing costs meant that the pistol was an unprofitable product for Remington despite its advanced design. In 2014 Remington launched the R51, chambered in 9x19mm using Pedersen’s hesitation lock, however the pistol suffered a number of problems and Remington recalled the first generation of R51s. A second, apparently improved, generation became available in 2016.
‘Automatic Firearm’, J.D. Pedersen, US Patent #1349733,
PA 2 / Prototype?