United States of America
10"/40 (25.4 cm) Mark 3
Updated 26 December 2008
The fast burning, smoky propellants of the 1800s gave way to the slower burning "smokeless" powders near the turn of the century.  These propellants gasified almost completely and could accelerate a projectile all the way along a gun barrel of 40 or more calibers long.  Thus the high-velocity naval gun was born.  A side benefit was the flatter trajectory, leading to more accurate firing which in turn led to centralized fire control.

In the case of the USN, the development of smokeless powder led to a new generation of long-barrel naval guns, including the 10"/40 (25.4 cm) Mark 3.  This weapon was one of the post Spanish-American War high-powered guns and armed the USN's last generation of armored cruisers.  This was the last 10" (25.4 cm) gun built for the US Navy.

In 1908 AP projectiles were fitted with a longer ballistic cap of 7crh which improved their penetration ability at longer ranges.

Consisted of A tube, jacket, four hoops, locking ring and a screw box liner, all manufactured from nickel-steel.
WNUS_10-40_mk3_Washington_pic.jpg

USS Washington ACR-11
(This ship was latter re-named USS Seattle)
.
Click here for additional pictures
.
.
Gun Characteristics
.
Designation 10"/40 (25.4 cm) Mark 3
Ship Class Used On Tennessee (ACR-10) Class
Date Of Design 1899
Date In Service 1902
Gun Weight 74,836 lbs. (52,834 kg) (including breech) 
79,500 lbs. (52,145 kg) (without breech)
Gun Length oa 413 in (10.490 m)
Bore Length 400 in (10.160 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist Uniform RH 1 in 25
Chamber Volume N/A
Rate Of Fire 2 - 3 rounds per minute
.
Ammunition
.
Type Bag
Projectile Types and Weights AP - 510 lbs. (231.3 kg)
Common - 510 lbs. (231.3 kg)
Bursting Charge AP - 13.25 lbs. (6.0 kg) Explosive D
Common - N/A
Projectile Length N/A
Propellant Charge 200 - 207 lbs. (90.7 - 93.9 kg) SP or SPD
Muzzle Velocity 2,700 fps (823 mps)
Working Pressure 16.0 tons/in2 (2,520 kg/cm2)
Approximate Barrel Life N/A
Ammunition Stowage per gun
(see Note)		 60 rounds
Note:  Wartime stowage was 72 rounds per gun.
.
Range
.
Elevation
With 510 lbs. (231.3 kg) AP Shell
MV = 2,700 fps (823 mps)
Striking Velocity
Angle of Fall
5.2 degrees
10,000 yards (9,140 m)
1,748 fps (533 mps)
6.9
5.9 degrees
11,000 yards (10,060 m)
1,676 fps (511 mps)
8.1
6.3 degrees
11,500 yards (10,520 m)
1,642 fps (500 mps)
8.7
14.5 degrees
20,000 yards (18,290 m)
---
---
Note:  Time of flight for AP Shell with MV = 2,700 fps (823 mps)
   10,000 yards (9,140 m): 13.9 seconds
   11,000 yards (10,060 m):  15.7 seconds
   11,500 yards (10,520 m):  16.6 seconds
.
Armor Penetration with 510 lbs. (231.3 kg) Shell
.
Range
Side Armor
Deck Armor
6,000 yards (5,490 m)
10.74" (273 mm)
---
9,000 yards (8,230 m)
8.21" (209 mm)
---
12,000 yards (10,920 m)
6.78" (172 mm)
---
This data is for face-hardened Harvey plates from "Ordnance Data Sheets" of 1905 and is for the older shell design.
.
Range
Side Armor
Deck Armor
6,000 yards (5,490 m)
12.1" (307 mm)
---
9,000 yards (8,230 m)
9.8" (249 mm)
---
12,000 yards (10,920 m)
7.8" (198 mm)
--- 
This data is from "Elements of US Naval Guns" of 1918 and is for the 7crh projectile.  Data is corrected for angle of fall and may also refer to harder armor than used for the 1905 data.
.
Mount / Turret Data
.
Designation Two-gun Turrets
  Tennessee (2):  Mark 6 (?)
Weight 275 tons (279 mt)
Elevation -3 / +14 degrees
Rate of Elevation N/A
Train about -150 / +150 degrees
Rate of Train N/A
Gun Recoil N/A
Loading Angle Any elevation
Notes:

1) Each gun was provided with a electric hoist that delivered two complete rounds per minute.  Automatic shutters were fitted in the ammunition supply tubes between the turret and magazines in order to increase flash protection.

2) Handling rooms were equipped with a tracked trolley system that helped in moving rounds to the hoists.

3) Turrets had a longitudinal bulkhead separating the guns and a turret officer booth.

4) These turrets used the "grass-hopper" counter recoil system whereby a spring box, located under the gun pit, was connected via two heavy, pivoted arms to the gun yoke.
.
Data from
"U.S. Cruisers:  An Illustrated Design History" and "US Naval Weapons" both by Norman Friedman
---
"Naval Ordnance - A Text Book" revised in 1915 by Lt. Cmdr. Roland I. Curtain and Lt. Cmdr. Thomas L. Johnson
"Range and Ballistic Tables 1935" by U.S. Department of Ordnance and Gunnery
"United States Naval Guns:  Their Marks and Modifications" Ordnance Pamphlet No. 127, December 1916, Second Revision June 1924
---
Gene Slover's Navy Pages
---
Special help from Wesley F. Moore