The Celmi submachine gun was one of the only SMGs to have been designed and produced in Uruguay, although the manufacturer, Fabrica de Armas Celmi hnos., was ran by two Italian brothers. This probably accounts for the obvious design inspiration from the Beretta Mod.38A submachine gun, of which the Celmi SMG can be considered a copy. It used the same basic layout as the Beretta, with some modifications. The cocking slot was on the right but was open instead of covered. The ejection port was not on the left, as per the Beretta, but on the right. The barrel was jacketed with rectangular perforations and a large muzzle brake similar. There was only one trigger, and the chambering was not in 9mm but in .45 ACP, which was a popular cartridge in South America. The Celmi submachine gun was developed in about 1946 but was not produced in any notable quantities.