76 mm divisional gun M1939 (USV)

76-mm divisional gun model 1939 (USV)
USV in Hämeenlinna Artillery Museum, Finland.
Type	Field gun
Place of origin	Soviet Union
Production history
Designer	Design bureau of No. 92 Plant, headed by V. G. Grabin
Produced	1939–1941
No. built	9,812
Specifications
Weight	combat:1,470 kg (3,240 lb) travel:2,500 kg (5,500 lb)
Length	5.95 m (19 ft 6 in)
Barrel length	3.2 m (10 ft 6 in) L/42
Width	1.94 m (6 ft 4 in)
Height	1.7 m (5 ft 7 in)
Crew	5
Shell	76.2 × 385 mm. R
Caliber	76.2 mm (3 in)
Carriage	split trail
Elevation	-6° to 45°
Traverse	60°
Rate of fire	15 rounds per minute
Maximum firing range	13.29 km (8.26 mi)

The 76-mm divisional gun M1939 (F-22 USV or USV) (Russian: 76-мм дивизионная пушка обр. 1939 г. (Ф-22 УСВ or УСВ)) was a 76.2 mm cannon produced in the Soviet Union. It was adopted for Red Army service in 1939 and used extensively in World War II. The gun was designated as "divisional" - issued to batteries under the direct control of division headquarters. The F-22 USV was an intermediate model, coming between the F-22, which had limited anti-aircraft capability, and the simpler and cheaper ZiS-3, which eventually replaced it in production and service.

The USV had a split-trail carriage with suspension; metal wheels with rubber tires were borrowed from the ZiS-5 truck. The gun featured semi-automatic vertical sliding breech block and Bofors-type cradle; recoil mechanism consisted of hydraulic recoil buffer and hydropneumatic recuperator. Sights and elevation controls were located on different sides of the barrel. The chamber fitted the standard model 1900 cartridge, which meant that the gun could use ammunition manufactured for older 76.2 mm divisional and regimental guns.

In 1937, unsatisfied with both the obsolete 76-mm divisional gun M1902/30 and the new, but flawed 76 mm divisional gun model 1936 (F-22), Red Army command (RKKA) initiated development of a new gun. The requirements, issued in March that year, specified elevation of 45° and combat weight of no more than 1,500 kg. The gun was supposed to have the same ballistics as the M1902/30 and use the same ammunition.

Three design bureaus joined the program - Kirovskiy Plant bureau under I. A. Makhanov, No. 92 Plant bureau under V. G. Grabin, and AKB-43 (KB AU) under M. N. Kondakov. The L-12 of Kirovskiy Plant was the first to reach ground tests (in April–May 1938), was returned for revision, tested again in August and given to the RKKA for further trials. Grabin's gun went through ground tests in March–April 1939 and was also given to the army. Although its designation - F-22 USV or simply USV - suggested that the gun was only an upgrade of the F-22, in fact it was a completely new design. The third competing project, OKB-43's NDP, failed ground tests in April 1939. RKKA tested the remaining designs from 5 June to 3 July 1939 and was generally satisfied with both of them. The USV was found to have less "childhood diseases" and was therefore recommended for production.