United States of America
4"/40 (10.2 cm) Marks 1, 3, 4, 5 and 6
4"/39 (10.2 cm) Mark 2
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Britain
4"/40 (10.2 cm) QF Mark XI
Updated 12 February 2012
Used as battleship and cruiser secondary weapons.  Mark 1 Mod 0 used bag ammunition, all others fired fixed ammunition.  Earlier guns were of layered built-up construction while later ones were hooped to the muzzle.  All of these guns used side-swinging carrier-type breech blocks and had similar performance.

Britain tried to obtain some of these guns to arm DAMS during World War I and even assigned a Mark number to them, but none could be spared from the USN's building programs.
WNUS_4-40_mk1_Iowa_pic.jpg

Early 4"/40 (10.2 cm) gun on USS Iowa B-4
Detroit Publishing Company Collection Photograph
Library of Congress Photograph ID LC-D4-20440
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Click here for additional pictures
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Gun Characteristics
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Designation USN:  4"/40 (10.2 cm) Marks 1, 3, 4, 5 and 6
British:  4"/40 (10.2 cm) QF Mark XI
Ship Class Used On Iowa (B-4), Columbia (C-12) and New York (ACR-2) classes
Gunboats Nashville (PG-7), Wilmington (PG-8) and Helena (PG-9)
Date Of Design About 1892
Date In Service 1897
Gun Weight Mark 1:  3,388 lbs. (1,537 kg) without breech
Mark 2:  3,398 lbs. (1,541 kg) without breech
Mark 3:  N/A
Mark 4:  3,160 lbs. (1,433 kg) with breech
Mark 5:  3,100 lbs. (1,406 kg) with breech
Mark 6:  3,529 lbs. (1,600 kg) with breech
Gun Length oa N/A
Bore Length 160.0 in (4.064 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist Increasing RH 0 to 1 in 25
Chamber Volume N/A
Rate Of Fire
(see Note)		 8 - 9 rounds per minute
Note:  During the 1905 target shoot off Culebra, Puerto Rico, one of USS New York (ACR-2) gun crews fired fourteen rounds in one minute and scored eleven hits.
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Ammunition
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Type Mark 1:  Bag
All others:  Fixed
Projectile Types and Weights AP - 33 lbs. (15 kg)
Common - 33 lbs. (15 kg)
Weight of Complete Round N/A
Bursting Charge N/A
Projectile Length N/A
Propellant Charge 4.85 lbs. (2.2 kg) SP or SPD
Muzzle Velocity 2,000 fps (610 mps)
Working Pressure Mark 1:  15.25 tons/in2 (2,400 kg/cm2)
Others:  15.5 tons/in2 (2,440 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
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Range
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Elevation With 33 lbs. (15 kg) HE Shell
Range @ 31.2 degrees 11,500 yards (10,520 m)
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Armor Penetration with 33 lbs. (15 kg) AP Shell
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Range
Side Armor
Deck Armor
3,000 yards (2,750 m)
1.7" (43 mm)
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6,000 yards (5,490 m)
1.2" (30 mm)
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Data from "U.S. Armored Cruisers" and is for KNC armor.
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Mount / Turret Data
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Designation Single Mountings:
   Central Pivot:  Marks 2 and 3
   Pedestal:  Marks 4, 7 and 9

Iowa (6), Columbia (8) and New York (12)
Helena (8), Nashville (8) and Wilmington (8)
Weight  Mark 2:  9,248 lbs. (4,195 kg)
Mark 3:  9,075 lbs. (4,116 kg)
Marks 4 to 7:  Between 7,700 - 8,600 lbs. (2,493 - 3,901 kg)
Elevation about -15 / +20 degrees
Elevation Rate Manual operation, only
Train about +150 / -150 degrees
Train Rate Manual operation, only
Gun recoil N/A
Notes:

1) The Mark 3 differed from the Mark 2 in having no directing bar, training was by handwheel with sights on the slide and being non-recoiling.  Many Mark 2 mounts were later converted to the Mark 3 standard.

2) Cruisers had eletrically-powered continuous chain ammunition hoists.
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Data from
"British Naval Guns 1880-1945 No 18" article by John Campbell in "Warship Volume X"
"U.S. Battleships:  An Illustrated Design History," "U.S. Cruisers:  An Illustrated Design History" and "US Naval Weapons" all by Norman Friedman
"U.S. Armored Cruisers:  A Design and Operational History" by Ivan Musicant
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"U.S. Explosive Ordnance:  Ordnance Pamphlet 1664 - May 1947" by Department of the Navy
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Tony DiGiulian's personal files
Page History

12 February 2008 - Benchmark
12 February 2012 - Updated to latest template and added mounting information