The Reffye 75mm was a French Field gun developed in the 1870's by Artillery General Jean-Baptiste Verchere de Reffye. The Reffye 75mm fired a 10.8 lb (4.9 kg) shell, making it the equivalent to the British 12lbers, such as the Armstrong BL 12lber.
The Reffye 75mm was designed with a breech loading mechanism, which was very complex for its time. This mechainsm consisted of a sliding breech block combined with a interrupted screw to lock the breech. In early examples the screw was made of bronze in an ill-fated attempt to produce an air tight seal. This would later be achieved with the invention of the de Bange obturator.
The carriage of the Reffye 75mm was a simple wheeled frame with a small tail to allow the Reffye to be rested on the ground. The Reffye 75mm would later be replaced by the more powerful de Bange 90mm which had the benefit of firing a more powerful shell whilst being of a lighter weight.
The Reffye 75mm was manufactured to fire France's equivalent to the British 12 lb shell. This shell actually weighed 10.8 lb (4.9 kg) which meant that the Reffye 75mm would fire at higher muzzle velocities than the equivalent British guns but was less powerful and had a reduced range.
The Reffye 75mm would only last a few years of military service, although its use can be traced to the 1890's. The Reffye 75mm would be replaced during its service, in large numbers, by the Lahitolle 95mm cannon (1875) and the de Bange 90mm (1877).
The Reffye 75mm would inspire the design of the Mitrailleuse (although the extent of which is debatable) which was among the first successful machine gun designs.