Staff Writer (Updated: 5/9/2016):
Despite Browning's work on long guns to this point, it would be the pistol that the Browning name would become synonymous with and his first successful design became the "Browning Model 1900" produced under the Fabrique Nationale brand. Browning's firearm accomplishments would then come to include the excellent Colt M1911, the Browning High-Power, the Winchester Model 1894, the Browning Automatic Rifle (the "BAR" of World War 2 fame), the Browning M2 heavy machine gun and the Browning M1919 general purpose machine gun.
The Browning Model 1900 became the first production pistol to use a slide assembly over the major working components and action of the firearm (now since a requisite of any semi-automatic handgun today). The original design was born in a 1896 initiative and brought to the attention of FN in 1898 to which the concern took to manufacture of the gun in 1899 as the "Modele 1899 (Mle 1899)". This became the first gun development of Browning's to be produced by the Belgian firm and began a long-running relationship that would continue until Browning's death in 1926 (hence its alternate name of "Browning No. 1"). Browning improved the design by shortening the barrel and this created the newer "Model 1900" mark of 1900. Production of this new type began soon thereafter to which some 700,000 examples were delivered.
The weapon operated from the blowback principle and was semi-automatic in its firing nature. The type was chambered for the 7.65x17mm Browning SR (.32 ACP) cartridge and fed form a 7-round detachable box magazine fitted into the base of the pistol grip. The weapon fielded an unloaded weight of 625 grams and a running length of 172mm with a 102mm long barrel. Sights were fitted at the front and rear of the slide top and fixed. Outwardly, the Model 1900 certainly held a unique design appearance with its rather clean surfaces and fine lines. Internally, however, the system utilized a rather unconventional arrangement in which the recoil spring was fitted over the barrel as opposed to under it. This gave the Model 1900 a rather awkward stance at first glance but, in effect, the arrangement led to reduced total internal parts. The return spring also doubled as the striker spring in the firing action. The pistol grip was fixed to the receiver and covered along its sides by a grip pattern.
While hundreds of thousands of Model 1900s entered circulation, the weapon did not see the type of military use that one might expect of a Browning design. National armies were suspect of the new automatic sidearm and the selection of the 7.65mm Browning cartridge did little to win them over - they instead choosing to rely on larger, more capable man-stopping rounds. As such, only a few national militaries ever requisitioned the type formally into their inventories (the Belgian Army being one such customer). The weapon went on to make appearances beyond Europe in several internal conflicts across Asia.
Despite many published sources claiming the gun used to kill Archduke Franz Ferdinand of Austria and sparking World War 1 being a Browning Model 1900, it was, in fact, a Browning Model 1910 (detailed elsewhere on this site). The actual weapon used in the assassination was showcased at the British Imperial War Museum as part of its Great War exhibition and this clearly depicted the Model 1910.
Production of the Model 1900 would only last eleven years which, considering the near-1 million production total, was certainly impressive given the rather short time span and its largely non-military usage. The Browning name continued with the establishment of the "Browning Arms Company" in 1927, one year after John Browning's death, and based out of Mountain Green, Utah. The company's goal was to deliver the successful Browning military firearms designs to the civilian market. The firm was eventually acquired by FN Herstal in 1977 and, as such, the Browning brand lives on today, primarily in the realm of sporting firearms as well as outdoor goods.