In 1941, when Romania entered the war alongside Nazi Germany, IOR was militarised and was tasked to produce mainly for the Romanian Army.

After the war, though the production continued under Soviet domination, the company maintained links to famous Western European firms such as Carl Zeiss AG, Leica, Pentacon and Schneider Kreuznach, which assisted IOR in its modernization and expansion in the 1970s.

As a consequence of Romania's refusal to join the invasion of Czechoslovakia, the Soviet Union ceased sharing technical information and exporting military equipment (including the newly designed SVD Dragunov).

IOR's LPS 4x6° TIP2 scopes are commonly found on Eastern Bloc sniper rifles such as the Puşca Semiautomată cu Lunetă, and SVD Dragunov.

Other manufacturers like the Russian Novosibirsk Instrument Making Plant and Belarusian Zenit company have not been as successful in entering the Western market.