A total of 12 production guns were built. Further production was curtailed because of the perceived low risk of war in the 1920s; by the time the need for more anti-aircraft artillery was obvious in the 1930s, the design was outdated.
The M/16 was employed in the static defence of the various military installations in Norway. The weapons were moved around as priorities shifted, but at the time the Germans invaded Norway on 9 April 1940, six guns were mounted near Bergen, four were mounted at the Naval base in Horten; the remaining two were near Oslo along with more modern weapons, such as the 7.5 cm L/45 M/32, to defend the capital.
The guns at Horten could have taken part in the battle that occurred in the harbour between Norwegian and German ships (see the article on HNoMS Olav Tryggvason for details), but due to unclear lines of command and the unprepared state of the crew, the guns were captured before any shots could be fired in anger.
In Bergen, the M/16 was used to try to shoot down German bombers attacking military targets, but the aircraft flew too low for the guns to be of much use. After the main fortification in Bergen surrendered to the Germans, the anti-aircraft batteries were ordered to stand down.
In Oslo, the two M/16s were mounted in a battery at Gressholmen - a small island in the harbour - and were ideally placed to take part in the battle for Fornebu. Norwegian sources claim this battery shot down one or two German bombers, despite the fact that the crew was untrained (17 out of the 44 men had been in uniform for only six days) and several became shell-shocked or deserted their posts. In addition to this and other problems, one of the guns jammed early-on in the engagement.
The fate of the M/16s after the Germans captured them is unknown, but it is likely they were used to further the German cause in Norway during their occupation of Norway.
