7.5 cm cannon 1903 L 30
| 7.5 cm cannon 1903 L 30 | |
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| General Information | |
| Manufacturer country: | Germany , Switzerland |
| Developer / Manufacturer: | Krupp, carriages later Federal Construction Workshop, Thun |
| Start of production: | 1903 |
| Weapon Category: | Field gun |
| Team: | 6 + 1 |
| Technical specifications | |
| Caliber : |
75 mm |
| Cadence : | 15 rounds / min |
| Furnishing | |
| Ammunition supply: | Breech loader |
The 7.5 cm cannon 1903 L 30 replaced the 8.4 cm Ord 1879 field gun ; it was the first gun used in Switzerland with a barrel return mount . The tube and the mount were manufactured in Germany by the Krupp cast steel factory in Essen . Changes to the mount resulted in the model 7.5 cm cannon 03/22 L 30 in 1922 . From 1940 the tubes were placed on expanding mounts manufactured by Sulzer in Winterthur ( 7.5 cm cannon 03/40 L 30 ), these modernized guns remained in use until the end of the Second World War.
Evaluation, history
Up until the 1970s, the tubes were mounted directly on the mount, when the gun was fired the gun ran back and had to be pushed back into the firing position and realigned. In order to increase the rate of fire of the field guns, a way had to be found to prevent their return. In the early nineties, attempts were made to achieve this with a movable earth spur attached to the mount, which braked the return of the mount and brought it back into the firing position by spring force.
Tests with this braking system were also carried out in Switzerland on the 8.4 cm Ord 1879 field gun and other 7.5 cm experimental guns from Krupp, Rheinmetall, St.Chamond and others. In the course of these tests, Krupp presented its latest development, a 7.5 cm gun with a barrel return. With this, a series of shots could be fired that hit the same target without having to realign the barrel. The Artillery Commission then recommended the purchase of a complete battery of these weapons for troop tests. On May 1, 1903, the Federal Council applied in its embassy to equip the field artillery with 7.5 cm Krupp cannons, which Parliament decided on June 23. Due to the higher firing performance of these guns compared to their predecessor, their number per battery was reduced from 6 to 4. In return, the number of batteries was increased from 56 to 72, resulting in an initial number of guns available for purchase of 288.
The gun
7.5 cm cannon 1903 L 30
The 7.5 cm cannon 1903 L 30 weighs 1096 kg when ready to fire and ready to drive with a protective shield. The gun barrel and breech block manufactured by Krupp are one-piece and made of solid steel. During firing, the system runs on the cradle 1350 mm and is returned by the built in the cradle recuperator brought back to normal position, a hydraulic brake system with 4 return springs. In contrast to its predecessor, the 8.4 cm Ord 1879/81/93 field gun, the horizontally inserted flat-wedge guide shaft lock no longer requires a linging ring, as the weapon fires case ammunition . The shot is ignited by the firing pin built into the breech, which strikes the primer located in the center of the case base. Total length of the tube 30 caliber or 2250 mm, caliber 7.5 cm. Progressive right-hand twist 3 ° 35 'to 5 ° 58'.
The steel single-arm carriage originally supplied by Krupp consisted of the lower carriage on which the tubular cradle was mounted so that it could pivot in height and side. Since the axis was attached above the lower mount, the fire height was only 0.995 m. The maximum height range of the cannon was limited to 240 artillery per mille. The horizontal swivel range was 3 ° on both sides. The 7.5 cm cannon 03 in its original form was therefore limited to the use of flat fire, a further restriction was the small adjustable side area, which made fighting moving targets more difficult. Overall length of the gun 3.9 m, width 1.68 m, track width 1.4 m.
7.5 cm cannon 1903/22 L 30
In 1922 the cannon was adapted to the new requirements of the army by Sulzer AG in Winterthur . The lower mount was increased by no longer being placed under, but over the wheel axle. this increased the fire height to about 1.22 m, which meant an extension of the height range to minus 175 to plus 400 artillery permille. The lower mount was widened and opened in the rear area to make room for the return pipe. To enable the gun to be transported in the mountains, the mount was made dismountable. The protective shield, originally in front of the axis, was moved behind it.
Elevation jacks were procured in 1927, the maximum barrel inclination was now 822 artillery permille. The gun was placed on the trestles with the help of rails attached to the trestles from behind. Later, in active service, the Bühler rail was developed, which could be rammed into the ground and thus absorb the recoil of the gun. The gun was mounted to pivot laterally, which led to a pivoting range of a total of 745 artillery permille, moving targets could now be fought better. The weight of the Bühler rail was 160 kg. It was mounted on the carriage for transport.
7.5 cm (anti-aircraft) cannon 1918 L 30
For anti-aircraft defense, the cannon 03/22 was pulled up on an approximately 3 m high bogie, this enabled a rotation of 360 ° and a firing angle of up to 1140 artillery bullets. In these cannons intended for anti-aircraft defense, stronger recoil springs had to be installed to allow the pipe to advance. In addition, the weight of the cradle and pipe had to be balanced with counterweights. The gun crew consisted of the gun chief and 9 men.
7.5 cm field cannon 03/40 L 30
Although it could not be overlooked that the effect of field cannons in caliber 7.5 mm was no longer sufficient for massive fire tasks, a number of guns were converted for the 7.5 cm motor cannon batteries. The tubes and top mounts of the 03/22 cannon were placed on expansion mounts manufactured by K + W. These 7.5 cm F Kan 03/40 L 30 guns could be deployed more quickly than the previous variations of the 03/22 model. They also had steel wheels with air chamber tires because they were pulled by trucks to transport them. A lowering device made it possible to change the height of the fire, by lowering it to 950 mm the stability of the gun could be increased, the maximum elevation of the barrel was 400 artillery bullets. At the highest fire height of 110 mm, it was possible to go up to 788 per thousand. The swivel range on both sides was a maximum of 1280 per thousand.
Ammunition used
The 7.5 cm cannon 03/22 L 30 initially fired shrapnel and high-explosive shells weighing 6.4 kg, later more modern projectiles were added which were also used in the 7.5 cm mountain cannon 1933 L 22 . The cases used held 3 unit charges, the bullet and case were loaded into the barrel as a unit. One was shot
- Steel grenade with double fuse (St G DZ), weight 6.4 kg
- Steel grenade with instant igniter (St G MZ), weight 5.75 kg
- Smoke grenade with instant igniter (RG MZ) weight 5.75 kg
- Pointed grenade with instant igniter (Sp G MZ), weight 5.95 kg
- Rauch pointed grenade with instant igniter (R Sp G MZ), weight 5.95 kg
- Tank shell
ballistics
When using the largest possible charge (Ladg. No. 3), the following initial speed v 0 and shooting distance were achieved:
- St G DZ, 485 m / s, 8700 m
- St G MZ, RG MZ, 503 m / s, 9150 m
- Sp G MZ, R Sp G MZ, 575 m / s, 11 800 m
literature
- Les Bouches à Feu de l'Artillerie Suisse, Author: Lt. Col. Jean de Montet, 1980, Edition du Center d'Histoire, Lausanne.
- Artillery II, recoil guns, author: Walter Betschmann, 1984, Verlag Stocker-Schmid, Dietikon-Zürich, ISBN 3-7276-7059-2
- Report of the Chief of the General Staff to the Commander-in-Chief of the Army on active service 1939–1945