Sweden 12 cm/50 (4.7") Model 1934/1936

Description

A Bofors design, this was modified and exported to Poland for arming destoyers and minelayers. The gun used a horizontal sliding breech block and was of loose barrel construction. Breech was manually worked.

Gun Characteristics

Designation	Sweden: 12 cm/50 (4.7") Model 1934/1936 Poland: 120 mm (4.7") SK L/50 M36/P
Ship Class Used On	Poland Destroyers: Blyskawica and Grom Poland Minelayer: Gryf
Date Of Design	1934
Date In Service	1937
Gun Weight	4.05 tons (4.115 mt) including BM
Gun Length	251.6 in (7.390 m)
Bore Length	about 236.2 in (6.000 m)
Rifling Length	N/A
Grooves	36
Lands	N/A
Twist	Increasing RH twist
Chamber Volume	885 in³ (14.5 dm³)
Rate Of Fire	about 10 rounds per minute

Ammunition

Type	Fixed
Weight of Complete Round	HE: 90.4 lbs. (41.0 kg)
Projectile Types and Weights	HE: 52.9 lbs. (24.0 kg)
Bursting Charge	N/A
Projectile Length	N/A Complete Round: 58 in (147 cm)
Propellant Charge	20.7 lbs (9.4 kg) Swedish 868 cal (WL)
Muzzle Velocity	2,953 fps (900 mps)
Working Pressure	20.95 tons/in² (3,300 kg/cm²)
Approximate Barrel Life	N/A
Ammunition stowage per gun	N/A

Range

Range with 52.9 lbs. (24.0 kg) HE
Elevation	Distance
30 degrees	21,300 yards (19,500 m)

Mount/Turret Data

Designation	Twin Mount Blyskawica (3), Grom (3) and Gryf (2): N/A Single Mount Blyskawica (1), Grom (1) and Gryf (2): N/A
Weight ¹	Twin Mount: 20.2 tons (20.5 mt) Single Mount: N/A
Elevation	-3 / +30 degrees
Elevation Rate	N/A
Train	about +150 / -150 degrees
Train Rate	N/A
Gun recoil	21.7 in (55 cm)

^Mount weight included guns and shield. Shield was 0.28 in (7 mm) thick and weighed 2.8 tons (2.85 mt).

Additional Pictures

Click for larger image. — Single 120 mm SK L/50 M36/P from Polish Minelayer *Gryf* now at the Polish Army Museum, Warsaw. Photograph copyrighted by Michal Kopacz.

Other Resources

Article on the 120 mm (4.7") SK L/50 M36/P in Polish service at Army 1914-1945.

Polish: 120 mm L/50 wz. 36 Bofors

English via Microsoft Translator: Bofors 120 mm L/50 Model 1936

Sources

"Naval Weapons of World War Two" by John Campbell
"Destroyers of World War Two" by M.J. Whitley
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Special help from Maciej Tomaszewski of Army 1914-1945

Page History

15 May 2006 - Benchmark
03 January 2009 - Corrected caption of twin mounting picture and number of guns on Gryf
13 August 2018 - Updated to HTML 5 format, added guns on Grom
28 August 2018 - Added links to Army 1914-1945
18 April 2021 - Added breech and complete rounds photographs