The concept, for what later became the "Nemesis" large caliber sniper rifle, was devised in 2001 by two former military, the retired US Marine Corps officer, James Owens and the Swiss Chris Movigliatti. First prototype was tested only 3 months after the design inception. In 2003, first production batch of rifles was made by AMSD, a Swiss company, highly specialized in the design of precision military light armament. The new weapon was officially christened as the OM 50 Nemesis (OM standing for names of the designers, 50 for caliber and Nemesis for the ancient Greek goddess of justice and vengeance)

Accuracy of the OM 50 rifles in field (real-life) conditions is described as 0,5 MOA at 300 meters and sub 1 MOA at 1000 meters; in testing, while fired by an experienced USMC sniper, OM 50 rifle shot 6x5 cm (about 2 1/2 inch) groups at 1000 yards (911 meters), which accounts for sub 0,25 MOA accuracy. The gun has already been commissioned with various police and military special operation forces.