SM-2-1

The 130 mm/58 SM-2-1 Pattern 1957 was a 130 mm 58 caliber Soviet naval gun. The gun was used as a destroyer weapon and it was also used as a coastal gun. Besides the Soviet Union, the gun was used on ships built by the People's Republic of China. The SM-2-1 was the main artillery system of the squadron destroyers of Project 41 and Project 56.

Background
The development of the SM-2 installation was started at the end of 1943 on the basis of the assignment of September 2, 1943 issued by ANIMI. The tactical and technical requirements for the installation were approved on April 25, 1944 by the head of the Naval Artillery Directorate. The development of the draft design involved the TsKB-34 under the direction of E. G. Rudyak. A draft design was submitted for approval on February 3, 1944. The project was based on technical solutions that were adopted by German designers during the development of the 105 mm caliber SKC-33 artillery system.

Plant number 232 for testing the installation was manufactured ballistic barrel CM-E11-130 and test site B-119. A rigid drum for a landfill machine was manufactured by plant number 190 SMEs. Experienced swinging part of the SM-2 was mounted September 30, 1948 on the ground testing machine B-120 (TT). The head sample SM-2 after manufacturing at factory No. 232 passed factory tests from April 5 to May 30, 1949 at the factory and from October 20 to December 12 of the same year - at the test site. The state tests of the installation took place in two stages: from May 10 to August 5, 1950, and from November 24, 1950 to March 30, 1951.

In 1950, according to the drawings of the prototype, corrected according to the results of field tests, plant number 232 manufactured two serial units SM-2-1. Installations were put on the lead destroyer of the project 41 " Fearless ". The state ship tests of the SM-2-1 at the Fearless were conducted in early 1955. The test report was signed on February 17, 1955. The next pair of serial units, manufactured at plant No. 232 in 1951, was delivered to the destroyer of Project 56 “ Tranquil ”, state tests of installation on the ship were carried out in two stages: in the Gulf of Finland from August 8 to September 8, 1955 and in the area of Baltiysk - Tallinn from December 3 to December 16, 1955 with a sea state of 4-5 points.

Mountings
An enclosed twin turret was developed for the SM-2-1; the tower installation is made armored to protect against fragments of shells and bullets.

Both installation tools are placed in the same cast cradle of the over- ride type. Each gun is equipped with a hydraulic spindle recoil brake, with a compensator (the brake is under the barrel), and a rammer. Above the barrel of each gun is a pneumatic knurler. Stabilization of the axle axles produced horizontally (in one plane). A rammer (pneumatic, with a rack accelerator) and a charger are capable of providing one-way delivery of separate-cartridge loading ammunition. Tray charger allows simultaneous laying of the projectile and shells. The ejection of powder gases is performed automatically.

An artillery installation could fire 54 volleys with a full rate of fire, after which it needed a 4–5-minute cooling of the barrels, carried out by pumping the barrel bore with outside water from the fire main. The maximum firing range was close to 28 km, and the height reachability was 21 km.

Service in Soviet Union
The 130 mm/58 SM-2-1 gun was used to arm the Project 41 and Project 56 destroyers built in Soviet Union. The gun was also used as a coastal gun. The coastal guns remained in use until the fall of the Soviet Union.

Service in China
The SM-2-1 was used as the main gun armament of the Luda-class destroyer.