Sweden
28.3 cm/45 (11.1") Model 1912
Updated 06 October 2007
A Bofors design, these were used on Sweden's Pansarskepp (Armored Ships) that were active between 1917 and 1947.  They were then kept in the reserve fleet until the late 1950s.  These guns were of built-up construction with a hand-operated screw breech-block of the Bofors ogival type.  They had a high rate of fire and were considered to be quite accurate.

In the 1930s a more aerodynamic "Arrow Nose Shell" was developed which gave an increased range.
WNSweden_11-45_m1912_Drottning_Victoria_pic.jpg

HMS Drottning Victoria
Picture courtesy of Joakim Wohlfeil
.
Click here for additional pictures
.
.
Gun Characteristics
.
Designation 28.3 cm/45 (11.1") Model 1912
Ship Class Used On Sverige Class
Date Of Design 1912
Date In Service 1917
Gun Weight 43.4 tons (44.1 mt)
Gun Length oa 501.4 in (12.735 m)
Bore Length about 484.1 in (12.295 m)
Rifling Length 414.0 in (10.515 m)
Grooves 80
Lands N/A
Twist Increasing RH 1 in 50 to 1 in 28
Chamber Volume N/A
Rate Of Fire 3 - 4 rounds per minute
.
Ammunition
.
Type Bag
Projectile Types and Weights AP - 672.4 lbs. (305 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 220.5 lbs. (100 kg)
Muzzle Velocity 2,854 fps (870 mps)
Working Pressure 19 tons/in2 (3,000 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
.
Range
.
Elevation With 672.4 lbs. (305 kg) AP Shell
Range @ 18 degrees 21,435 yards (19,600 m)
Elevation With 672.4 lbs. (305 kg) Arrow Nose Shell
Range @ 20 degrees 26,250 yards (24,000 m)
Range @ 25 degrees 31,700 yards (29,000 m)
.
Armor Penetration with 672.4 lbs. (305 kg) AP Shell
.
Range
Vertical KC Armor
Horizontal Armor
6,560 yards (6,000 m)
350 mm
---
19,690 yards (18,000 m)
155 mm
87 mm
Note:  Data from Bofors proof testing as detailed in "Från monitorer till pansarskepp."
.
Mount / Turret Data
.
Designation Two-gun Turrets
   Sverige (2)
Weight  348.1 tons (353.7 mt)

One sources says 406 tons (413 mt)
Elevation
(see Note 1)		 As built:  -5 / +18 degrees
Elevation Rate 5 degrees per second
Train about +150 / -150 degrees
Train Rate 4 degrees per second
Gun recoil 28.7 in (73 cm)
Loading Angle 0 degrees
Notes:

1) "Naval Weapons of World War Two" says that some reports state that the elevation was increased to 35 degrees.  However, Joakim Wohlfeil informs me that the maximum elevation for these guns never exceeded 25 degrees.  "Från monitorer till pansarskepp" says that increases were contemplated but never carried out due to financial restrictions and that the elevation may never have exceeded 19 or 20 degrees.

2) Gun axes were about 83 in (210 cm) apart.
.
Data from
"Naval Weapons of World War Two" by John Campbell
"Från monitorer till pansarskepp" by Per Insulander and Curt S. Ohlsson
---
Special help from Stefan Bengtsson and Joakim Wohlfeil