ASU-57

The ASU-57 was a small, lightly constructed Soviet assault gun specifically designed for use by Soviet airborne divisions. From 1960 it was replaced by the ASU-85.

Development history
The task to develop a light-weight airborne assault gun with 57 or 76mm gun for the airborne troops was given to two design bureaus, Astrov (OKB-40) in Mytishchi and Kravtsev in Moscow. Nikolaj Astrov's OKB-40 designed the ASU-76, based on components of the light tank T-70 and the SU-76 assault gun, and armed with the new 76mm gun D-56T. The ASU-76 turned out to be too heavy, even though the armour was only 3 mm thick, and the project was cancelled. Anatoly Kravtsev's team came up with the similar, amphibious K-73. This vehicle was armed with Charnko's 57mm anti-tank gun Ch-51 and was even more thinly armoured than the ASU-76. This project too was shelved.

In 1949, Astrov was instructed to continue with his project, but with reduced weight and with the Ch-51 gun as main armament instead of the D-56T since it offered better anti-tank performance. The redesigned Ob.572 was developed simultaneously with the light artillery tractor Ob.561 (AT-P) and was accepted for series production from 1951 as the ASU-57, after successfully passing the various test phases in 1949.

Design
The ASU-57 was designed to be a light-weight assault gun that could be air-dropped and deployed by rocket-assisted parachute (PP-128-500 or P-7) along with the troops. It was lightly armored and armed with a 57 mm gun Ch-51, a development of World War II ZIS-2 but with some similarities to the Ch-26. From 1954, an improved 57mm gun Ch-51M with much shorter double-baffle muzzle brake was fitted. The gun fired standard caliber 57x480R ammunition of the ZIS-2 anti-tank gun, such as the BR-271 series and the O-271U, of which it had 30 on board. The ASU-57's engine was taken from the GAZ-M-20 "Pobeda" civilian car.

The ASU-57 was a successful design, and saw service with Soviet airborne divisions for around 20 years before being replaced by the ASU-85. During its years of operation 54 vehicles would have been assigned to each airborne division.

One main drawback was the vehicle's welded aluminum hull, which offered little protection for the crew. However for airborne troops such vehicles are invaluable, giving lightly armed soldiers who are isolated behind enemy lines mobile artillery support on the battlefield.

Every vehicle was equipped with a radio 10 RT-12 and intercom system TPU-47. Late-production models (from 1961) had the R-113 and R-120, as well as a TVN-2 night vision device for the driver.

Variants



 * ASU-57KShM - An unknown number of ASU-57s were converted into command and staff vehicles (командно-штабная машина). These had the gun removed and were fitted with additional signals equipment.
 * BSU-11-57F or 2T2 - Recoilless gun carrier for the B-11 of 107mm. Prototype only.
 * ASU-57P or Ob.574 - From 1951, work on an amphibious (плавающая) variant of the ASU-57 started. This version had a re-designed front hull and was armed with a Ch-51P gun with 30 rounds. Even though the 5 prototypes passed the evaluation with success, series production was never started.