The INA MB-50 submachine gun (Metralhadora de mão INA Modelo Brasiliero 1950) was manufactured by Brazilian small arms company Industria Nacional de Armas S/A. It was a licensed copy of the Danish Madsen model 1949 submachine gun, with minor alterations regarding its caliber (.45ACP as opposed to the original 9×19 chambering).
The original gun was produced only between 1950 and 1953, after which, a slightly improved INA M/953 submachine gun, with extended magazine housing was introduced. It chambered the same .45ACP ammunition, and was extensively used by the Brazilian police and military. During the 1980’s a number of both of these submachine guns still in service were converted to fire 9×19 Luger ammunition. There were several slightly different modifications in the 9mm version. These are listed at the bottom of the page.
This weapon is simple blowback operated. It fires from an open bolt in full automatic mode only. The receiver, along with pistol grip and magazine housing, is of clamshell design. It’s pressed from two halves of sheet steel and joined together, left side and right side. These halves are connected by stock axis pins at the rear, and by a screw-on barrel nut at the front.
The charging handle is located on the right and permanently attached to the bolt. A manual safety is located above the trigger, on the left side of the gun. There is also an automated safety lever which must be disengaged by gripping it toward the magazine housing by the left hand. Ammunition is fed from detachable box magazines, which are of double stack, single feed design. Sights are fixed, with aperture rear sight set for 100 meters range. The shoulder stock is a steel wire frame and folds to the side.
|Full text name||INA MB-50 submachine gun (Brasil)|
|Caliber cartridge||.45 ACP .45 Automatic Colt Pistol (11.43x25)|
|Overall length, mm||793|
|Length, folded, mm||545|
|Barrel length, mm||214|
|Weight empty, kg||3.4|
|Magazine capacity, rounds||30|
|Cyclic rate of fire, rounds/min||650|
INA M/953 submachine gun: featuring extended magazine housing
INA 9 submachine gun: M/953 submachine guns converted to 9×19. Featuring new barrels with integral muzzle compensators, and three position, rotary safety/selector levers.