Editing FN Model 1949 (section)

=== Development ===
Dieudonne Saive, [[Fabrique Nationale de Herstal|Fabrique Nationale]]'s then chief firearm designer, experimented with a number of [[recoil operation|recoil-operated]] rifle designs in the early 1930s. While little came of these experiments, they would become the basis for a gas-operated [[semi-automatic rifle]], which he patented in 1936 and prototyped in 1937. (Photographs of these prototypes still exist, and they show a number of characteristics that would later appear in the FN-49.)

FN's new rifle was still in development in late 1938 – early 1939, and a version with a 5-round magazine was about to be marketed. When German armies invaded Poland, these plans were delayed to increase production of bolt-action rifles and machine guns.

The [[Battle of France|German invasion of Belgium in May 1940]] interrupted any plans for the production of the new model, as [[Liège]], home of FN's factory, was occupied by the German military. Despite this setback, Saive was able to escape to England via Portugal in 1941, where he continued work on what would become the FN-49.

By 1943, Saive was back to working on his experimental rifle, now in [[7.92×57mm Mauser]]. Late that year, [[Royal Small Arms Factory|the Royal Small Arms Factory, Enfield]] ordered 50 prototypes (designated "EXP-1" and sometimes referred to as "[[SLEM-1]]" or "Self-Loading Experimental Model"). Based on tests with these prototypes, Enfield placed an order for 2,000 rifles for troop trials, but a last-minute problem with the moderation of the gas pressure (as well as the impending end of [[World War II]]) led to the cancellation of this order. Despite this, Saive (who had returned to Liège shortly after its liberation in September 1944) continued work on the rifle, and finalized the design for the FN-49 in 1947.

The FN Model 1949 is not ammunition specific, since it has an adjustable gas port or valve to adjust the rifle to various propellant and projectile specific pressure behavior, in which the gas port can be adjusted with a special wrench.  This also requires removing the upper forward handguard for the adjustment.