FN HP-DA

FN HP-DA ("Hi-Power Double Action") is a 9mm semi-automatic pistol developed by Belgian Fabrique Nationale arms factory in Herstal. In North American markets, it was marketed as Browning BDA ("Browning Double Action", also BDA9) and is also referred to as Browning DA and Browning Hi-Power BDA.
Introduced in 1983, it is an update of the Browning Hi-Power (a.k.a GP 35 in Belgium and French-speaking countries). The overall design layout of all versions of the pistol is based on the Browning Hi-Power, but the firearm features significant ergonomic changes designed to update the weapon to military requirements of its time. 
Overview.
The BDA represents the further development of the widely used FN/Browning Hi-Power, which, by 1980s, had been production for almost 50 years before design on BDA was completed. The development of the BDA may have been response to original Hi-Power's shortcomings in the first Joint Service Small Arms Program tests conducted in late 1970s.
FN had the HP-DA ready for the 1983–1984 XM9 pistol trials to select new sidearm chambered for the 9×19mm Parabellum cartridge that would equip all the branches of the United States armed forces. Ultimately, the winner of the bid was the Italian Beretta 92F.
The Finnish Defence Forces accepted the weapon into service as their general service pistol under the designation 9.00 PIST 80 and 9.00 PIST 80–91.
The FN HP-DA/Browning BDA had two versions during its lifetime. The "first version" featured a frame safety similar to original Browning Hi-Power. Production of FN HP-DA started in 1983, but did not sell well and was withdrawn from the markets in 1987. 
The production resumed in 1990, with the "second/updated version" produced with a newer style frame safety, as well being made with a new manufacturing process. Along with the second version, in 1990, new variations, such as compact (BDAC/HP-DAC) and double-action only (BDAO/HP-DAO) variants also entered production. Ultimately the production of BDA and its variants would cease in 1999. It would be succeeded by FN Forty-Nine in 2000 and then FN FNP in 2006.
Design details.
The FN HP-DA is a semi-automatic short recoil operated locked breech firearm. It has a vertically tilting delayed camming action. This locking mechanism was borrowed from the Browning Hi-Power. The handgun features a double-action trigger which cocks and then releases the hammer. The recoil of the slide recocks the hammer, and all consecutive shots are fired from the single-action mode. A disconnector ensures the pistol fires in semi-automatic mode only. The spring-loaded external claw extractor is mounted in the slide, while the fixed ejector – inside the pistol’s frame. The BDA is secured against unintentional firing with an automatic firing pin safety which blocks the firing pin and is released only when the trigger is pulled to fire. Immediately after a round is fired, the safety reengages itself even if the trigger is not released. The BDA also has a decocking safety that safely releases and captures the hammer in a safety notch. A decocking lever is mounted on each side of the pistol’s frame.
Compared to original Browning Hi-Power, one its most notable changes is the shortening of the hammer spur, which would tend to cut into the web between the thumb and fingers of the grip hand if an original Hi-Power was held incautiously.
The HP-DA feeds from a dual-column box magazine with a 14-round cartridge capacity. (The FN HP-DA however uses a different 10- or 15-round magazine which is interchangeable with the Browning BDM but will not fit in a Browning BDA-9 though the guns look identical and they are both made by FN Herstal.) The magazine release button, located aft of the trigger, can be configured for either right- or left-hand users simply by swapping out the push-button. The BDA is fitted with a slide catch that holds the slide open after depleting the magazine. The slide can be released by pressing the slide release lever, placed on the left side of the frame. The pistol is aimed using fixed iron sights with contrasting dots – a front blade and dovetailed rear notch. As an option, tritium-illuminated Meprolight night sights can also be fitted.
The HP-DA is chambered in the 9×19mm Parabellum cartridge, but a 9×21mm version is also available for those countries where military calibers (such as the 9×19mm) are prohibited for civilian use.
Variants.
Originally, the BDA/HP-DA was produced only as a standard model during its first version in 1983–1987. When the second/updated version was introduced in 1990, FN also introduced new variants of the BDA/HP-DA pistol. The Browning Hi-Power BDA/FN HP-DA was produced in following variants:
Presently, Fabrique Nationale no longer advertises the pistols in their sales offerings.