7.5 cm L/45 M/16 anti aircraft gun

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7.5 cm L/45 M/16

The patent drawing of the 7.5 cm L/45 M/16 anti aircraft gun
Type Anti aircraft gun
Place of origin Norway
Service history
In service 1925 - 1940
Used by Norway
Wars World War II
Production history
Number built 12 + 1
Specifications
Weight  ??
Barrel length 45
Crew 9
Shell HE and shrapnel
Caliber 75 mm
Carriage Static
Rate of fire  ??
Muzzle velocity 750 m/s
Effective range 8000 m

The 7.5 cm L/45 M/16 anti aircraft gun was designed and manufactured in Norway in the early to mid 1920s. It was an uninspired design, but it did boost the anti aircraft capacity in Norway significantly when adopted.

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[edit] Background and design

Early in World War I, the Norwegian Army realised that aircraft was a threat that needed to be countered. At first attempts were made to mount existing field guns on new mounts to allow high angle fire, but it was soon obvious that more a more specialised weapon was needed. At first attempts were made to buy British and French guns, but both nations needed the weapons themselves because of the ongoing war.

The history of the M/16 can be traced to a letter from the Norwegian Ministry of Defence dated 17 December 1915. After initial design work had been carried out, it was decided to manufacture 1 prototype and 12 production cannons. The detailed design work took longer than anticipated, and with the end of the war the urgency seemed to leave the project. Due to this the prototype was not ready for test firing until 20 May 1920.

The M/16 was a relatively simple design. It was intended for static emplacement, and was mounted on a pedestal, allowing for 360° sideways movement. The mount allowed for elevations between -1° and 75°. The gun barrel was 45 calibers long, and had 28 rifles twisting to the right. The breech block was a semi automatic horizontal wedge - the gunner had to manually open it to remove the case from the previous shoot, but it closed automatically on insertion of a new round. Under the barrel was a hydro-pneumatic recoil cylinder with a heavy spring to aid the forward motion of the gun at high elevations. Originally it was designed to fire under local command, but was later equipped to receive gun-laying information from a central sight.

The gun was also equipped with a device for automatically adjusting the time fuses on the shells.

The M/16 was served by a crew of nine: The gun commander, one solder for adjusting sideways, one for adjusting elevation, one to operate the breech block and fire, one loader, one 'fuse adjusting device operator', one 'fuse adjuster' and two to fetch ammunition and take away the shell casings.

[edit] Service history and fate

A total of 12 production guns were made. Further production was curtailed because of the perceived low risk of war in the 1920's, and when the need for more anti aircraft artillery was obvious in the 1930's, the design was outdated.

The M/16 was employed in static defence of the various military installations in Norway. They were moved around as the priorities shifted, but at the time the Germans invaded Norway on 9 April 1940, 6 were mounted near Bergen, 4 were mounted at the Naval base in Horten, and the remaining 2 were near Oslo along with more modern guns to defend the capital.

The guns at Horten could have taken part in the battle that took part 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 6 days) and several became shell shocked or deserted their posts. In addition to this and other problems, one of the guns got 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 by the Germans in Norway during the war.

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