Eventually transferred to the command of the Army develop a machine gun designers running Olympio Vieira de Mello. In the 76th, he made a significant change in the model. At the end of '77 Institute for research and development, the Ministry of Defence issued the company "Mekanika industry of e-commerce Ltda" contract to develop a pair of experienced models. At the trials gun proved to be excellent and in 1979 was adopted by the Brazilian Army. After that began the creation of machine guns for the needs of the Brazilian armed forces, and for the implementation of the limit. The machine gun was called "Uirapuru" — on behalf of the bird that lives in the Brazilian tropical undergrowth (mixed with the title of the manufacturer — Uirapuru Mekanika, «Uirapuru Mekanika"). Create been prepared at the plant near Rio de Janeiro.
Automatic machine gun operated by the removal of the powder gas through a hole made on the right side of the trunk. The gas control is absent. The gas chamber and bipod installed on the bracket which is a continuation of the front receiver. Declining larva closes the bore. Gun only has a continuous mode of fire. Fuse located above the pistol handle, can be mounted in two positions: fuse — «SAFE» and fire — «AUTOMATIC». Nutrition is a cartridge gun belt that meets the standards of NATO. Carrying handle situated on the trunk. It also serves as a substitute for it. Substitute trunk recommended after 400 shots. Muzzle brake arrester having perforations located at the end of the barrel. Receiver box slightly longer than the usual form of pipes, which are contained in the bolt and spring revertible. The receiver under the tape is made in the form of the receiver cover. The feeder belt — lever type. Single gun "Uirapuru Mekanika" — comparable to very long, with all this quite successful in carrying also set in position.
Sights: front sight is adjustable both horizontally and vertically, and the sight, having a divide-by-200, 600 meters and divide by 800 to 1,400 meters. The sight and front sight with the sides covered with "ears", their location on the receiver is due to the small length of the sighting of the strip.
Use different variants of a machine gun, "Uirapuru": manual (with bipod and butt), medium machine (the machine on the tripod, without stock) coupled tank (to equip electric trigger), anti-aircraft and so on. The machine gun is mounted on the machine cradle for front and rear lugs made from below the receiver.
Technical properties of a machine gun, "Uirapuru Mekanika":
Cartridge — 7,62 x51;
Weight — 13 kg;
Length — 1300 mm;
Barrel length — 600 mm;
Rifling — 6 of right;
The stroke length of rifling — 305 mm;
The initial velocity — 850 m / s;
Rate of fire — 650-700 rounds per minute;
Tape capacity — 50 rounds.