After World War II the Belgian Army was equipped with a mixture of British and American guns.

The army wanted to replace these weapons with modern designs of preferable Belgian origin.

Some parts were subcontracted to the State Arsenal at Rocourt in Liège, who eventually began making complete guns.

An unconfirmed story says that the CMH inscription on the grip means Compagnie de Manufacture Herstal, and this company is supposed to have made the plastic lower receiver.

Some sources state that many M1's were reworked to M2 standard by fitting hood over foresight, changing the rear sight and fitting a stronger spring to the ejection port cover and that when this upgrade was done the M1 designation was overstamped M2, but examples of M1's that have been upgraded to the M2 exist where the original M1 stamp has not been over stamped.

The stock is heavy steel rod and it telescopes along the receiver; one end is slotted for swabs and the other is threaded for a cleaning brush.

The "Cutts" type barrel compensator and cooling rings are reminiscent of the Thompson submachine gun, the wire stock looks like the M3 submachine gun, the bolt design is nearly identical to the Sten and the magazine is almost the same as the one designed for the MP40.