Info on USA big ship guns.
Gun Characteristics Designation 18"/48 (45.7 cm) Mark 1
16"/56 (40.6 cm) Mark 4
18"/47 (45.7 cm) Mark "A"
Ship Class Used On 1 None (Experimental)
Date Of Design 1920
Date In Service Never mounted aboard ship
Prototype:
As 18"/48 (45.7 cm): Never finished in this configuration
As 16"/56 (40.6 cm): 1927
As 18"/47 (45.7 cm): 1942
Gun Weight 18"/48 (45.7 cm): 177.8 tons (180.7 mt)
16"/56 (40.6 cm): 185.2 tons (188.2 mt)
18"/47 (45.7 cm): 177.0 tons (179.8 mt)
Gun Length oa 18"/48 (45.7 cm): 884.0 in (22.454 m)
16"/56 (40.6 cm): 915.0 in (23.241 m)
18"/47 (45.7 cm): 865.0 in (21.971 m)
Bore Length 18"/48 (45.7 cm): 864 in (21.946 m)
16"/56 (40.6 cm): 896 in (22.758 m)
18"/47 (45.7 cm): about 846 in (21.488 m)
Rifling Length 18"/48 (45.7 cm): 737.263 in (18.727 m)
16"/56 (40.6 cm): 765.712 in (19.449 m)
18"/47 (45.7 cm): 718.965 in (18.262 m)
Grooves 16"/56 (40.6 cm): 96 grooves
Others: N/A
Lands N/A
Twist 18"/48 (45.7 cm): Uniform RH 1 in 32
16"/56 (40.6 cm): Uniform RH 1 in 35
18"/47 (45.7 cm): Uniform RH 1 in 25
Chamber Volume 18"/48 (45.7 cm): 36,900 in3 (604.7 dm3)
16"/56 (40.6 cm): 34,000 in3 (557.2 dm3)
18"/47 (45.7 cm): 36,900 in3 (604.7 dm3)
Rate Of Fire about 1.5 - 1.75 rounds per minute
- ^Although this weapon was extensively considered in numerous battleship design studies of the 1920s and 1930s, it was never formally selected for any ship. The last US battleship design, the cancelled USS Montana (BB-67) class, would have carried the same 16"/50 (40.6 cm) Mark 7 guns as did the previous USS Iowa (BB-61) class.