Browning Automatic Machine Rifle Type D with detachable barrel

The FN Browning Automatic Rifle model D, often referred to simply as “FN Model D” or “FN Type D” or just “FN D” was an ultimate step in evolution of the Model 1930 Browning Automatic Rifle, as built by FN, which, in turn, was an iproved version of the US M1918 BAR. The “D” stands for “Demontable”, which means quick-detachable barrel. The Model D appeared in around 1932, with the key improvement being the quick-detachable barrel and simplified disassembly procedure (achieved by hinging the buttstock to the receiver at the top and making the pistol grip / trigger unit easily removable). The barrel lock was placed on the right side, in front of the receiver, and the barrel was fitted with a folding carrying handle. In Belgian service, FN D machine guns were often issued with special sustained fire tripods of folding design, with traverse and elevation mechanisms. The FN D was manufactured in a variety of calibers, and since 1957 a number of FN D machine guns was converted to 7.62x51 NATO caliber for Belgian Army. This version was known as FN D A1 and utilized FN FAL rifle magazines.
The basic functioning of the FN D is same as of US M1918 BAR, with certain differences in trigger unit, sights, stock layout and, most important, addition of the quick-detachable barrel and different, more rapid disassembly / reassembly procedure.