102mm 60 caliber Pattern 1911

102mm 60 caliber Pattern 1911
A 102mm gun aboard the Finnish gunboat Uusimaa.
Type	Naval gun Railway gun Coastal artillery
Place of origin	Russian Empire
Service history
Used by	Russian Empire Soviet Union Bulgaria Estonia Finland Peru
Wars	World War I Russian Civil War Winter War World War II
Production history
Designer	Vickers
Designed	1908
Manufacturer	Obukhov Perm
Produced	1911
Specifications
Weight	2,850 kg (6,280 lb)
Length	6 m (19 ft 8 in)
Barrel length	5.2 m (17 ft 1 in) 60 caliber
Shell	Fixed QF 101.6 x 790mm R ammunition 30 kg (66 lb)
Shell weight	17.5 kg (39 lb)
Caliber	102 millimeters (4.0 in)
Action	Semi-automatic
Breech	Horizontal wedge breech
Elevation	-10° to +30°
Traverse	360°
Rate of fire	12-15 rpm
Muzzle velocity	823 m/s (2,700 ft/s)
Effective firing range	16 km (9.9 mi) at +30°

The 102mm 60 caliber Pattern 1911 was a Russian naval gun developed in the years before World War I that armed a variety of warships of the Imperial Russian Navy during World War I. Pattern 1911 guns found a second life on river gunboats and armored trains during the Russian Civil War and as coastal artillery during World War II. In 1941 it was estimated that 146 guns were in service. Of these, 49 were in the Baltic Fleet, 30 in the Black Sea Fleet, 30 in the Pacific Fleet, 18 in the Northern Fleet, 9 in the Caspian Flotilla and 6 in the Pinsk Flotilla.

The requirement to re-equip destroyers of the Imperial Russian fleet with guns larger than the current 75 mm 50 caliber Pattern 1892 was raised by the chief of the Baltic Fleet Mine Division, Nikolai Ottowitsch von Essen, in January 1907. The design for the new gun was completed with technical assistance from the British Vickers company at the Obukhov State plant in 1908 and testing was completed in August 1909.

Pattern 1911 guns were produced at the Obukhov state plant and the Perm artillery factory between 1911 and 1921. In 1911 an order for 505 guns was placed of which 225 were delivered by January 1, 1917. Another 200 were expected to be produced during 1917 and 83 in 1918. In 1921 an order for 85 guns was placed at the Perm factory, but this was reduced to 48 guns. The Pattern 1911 was constructed of an A tube, reinforced by three hoops which were put on while hot and screwed onto the breech. The Pattern 1911 had a high rate of fire 12-15 rpm (10 rpm practical) due to the use of Fixed QF ammunition and a semi-automatic, horizontal wedge breech mechanism. After ejecting each empty case the gun re-cocked itself and kept breech open for the next round. It also had the usual combination of hydraulic buffer and spring recuperator. The original naval mounts were short and had low angles of elevation between -6° to +20°. Latter mounts were taller and had high angles of elevation between -10° to +30°.