United States of America
6"/47 (15.2 cm) Mark 17
Updated 18 May 2007
This was a variation of the previous 6"/47 (15.2 cm) Mark 16 and was used only on the Erie (PG-50) class of Patrol Gunboats.  Unlike the Mark 16, the Mark 17 was designed for bag ammunition.

The mountings for these weapons were unusual for this type of ship, as they had power elevation and training.

Constructed of a chrome-platted autofretted barrel attached to a breech housing by interrupted threads.  Used a side-swing breech mechanism.
WNUS_6-47_mk17_Erie_pic.jpg

USS Erie PG-50 in September 1942
Circled areas represent recent changes, in this case a new Mark 3 Radar atop her Mark 35 director, new radio antennas and bridge modifications
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Gun Characteristics
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Designation 6"/47 (15.2 cm) Mark 17
Ship Class Used On Erie Class
Date Of Design 1933
Date In Service 1938
Gun Weight 5.24 tons (5.32 mt)
Gun Length oa 289.0 in (7.341 m)
Bore Length 282.3 in (7.169 m)
Rifling Length about 238.3 in (6.053 m)
Grooves N/A
Lands N/A
Twist Uniform RH 1 in 30
Chamber Volume 1,478 in3 (24.22 dm3)
Rate Of Fire 5 - 8 rounds per minute
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Ammunition
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Type Bag
Projectile Types and Weights Common Mark 28 Mods 1 and 2 - 105 lbs. (47.6 kg)
Illum Mark 22 Mod 1 - 95.40 lbs. (43.3 kg)
Illum Mark 23 Mods 1 and 2 - 96.0 lbs. (43.5 kg)
Bursting Charge Common Mark 28 Mods 1 and 2 - 5.72 lbs. (2.6 kg) Explosive D
Projectile Length 27 in (68.6 cm)
Propellant Charge 34.5 lbs. (15.7 kg) NC
34.0 lbs. (15.4 kg) SPD or SPDN
Muzzle Velocity Common - 2,800 fps (853 mps)
Working Pressure 18.5 tons/in2 (2,910 kg/cm2)
Approximate Barrel Life 750 - 1,050 rounds
Ammunition stowage per gun N/A
Notes:

1) Propellant was in a single bag.

2) Bourrelet diameter was 5.985 inches (15.2 cm).
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Range
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Elevation 105 lbs. (47.6 kg) Common Shell
Range @ 20 degrees 19,800 yards (18,100 m)
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Mount / Turret Data
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Designation Single Pedestal Mounts
   Erie (4):  Mark 18
Weight  15.4 tons (15.65 mt)
Elevation -10 / +20 degrees
Elevation Rate N/A
Train about +150 / -150 degrees
Train Rate N/A
Gun recoil 24 in (61 cm)
Loading Angle N/A
Note:  Used 3.5 hp motors for elevation and training.
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Data from
"Naval Weapons of World War Two" by John Campbell
"US Cruisers:  An Illustrated Design History" and "US Naval Weapons" both by Norman Friedman
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"U.S. Explosive Ordnance:  Ordnance Pamphlet 1664 - May 1947" by Department of the Navy