8-inch Gun M1

8-inch Gun M1
8 inch Gun at the U.S. Army Field Artillery Museum, Fort Sill, OK
Type	Heavy gun
Place of origin	United States
Service history
Used by	United States United Kingdom
Wars	World War II
Production history
Designed	1939–1942
Produced	1942-1945
Specifications
Weight	Combat: 69,300 lb (31,400 kg)
Barrel length	33 ft 4 in (10.16 m) L/50

Shell	separate-loading, bag charge
Caliber	203 mm (8.0 in)
Breech	interrupted screw
Recoil	hydropneumatic
Carriage	split trail
Elevation	+10° to +50°
Traverse	30° (initially), post-war 40°
Muzzle velocity	2,840 ft/s (870 m/s)
Effective firing range	12.5 mi (20.1 km) (minimum)
Maximum firing range	20.24 mi (32.57 km)

The 8 inch gun M1 was a 203 mm towed heavy gun developed in the United States. At 32,584 m (35,635 yds.), it had the longest range of any US Army field artillery weapon in World War II. It was also used in small numbers by the British Army.

Development and Production

In 1919, the Westervelt Board described the ideal heavy gun for future development having a bore of 194mm to 8-inches, a projectile of about 200 lbs, and a range of 35,000 yards. More striking was that it be must be road transportable. At this time no other country had such a road transportable field gun.^[1] Low priority design work occurred until 1924. Serious development began in June 1940 of an 8-inch (203 mm) gun that would have a range of 33,500 yards (30,600 m), a road speed of 25 mph (40 km/h), be transported in 2 loads weighing no more than 44,000 lb (20,000 kg) and be suitable for rail movement. The gun used the same projectile as the 8 inch coastal gun and the US Navy's 8 inch cruiser gun.^[2] Using the same carriage as the 240 mm howitzer M1 eased development, but the gun was very troublesome and wasn't standardized until January 1942. The main problems were excessive bore wear and poor accuracy, but it was felt that nothing better could be produced in a timely manner. Thus it entered production at a low rate and in small numbers. The gun tube was produced by Watervliet Arsenal and the recoil system was produced by Hannifin Manufacturing. Watertown Arsenal, Bucyrus-Erie, and the S. Morgan Smith Company manufactured the carriage. Only 139 weapon systems were produced before production ceased in 1945.^[3]

In the quest for greater tactical mobility, the Ordnance Department experimented with a self-propelled version. Like the 240 mm howitzer, it was mounted on a stretched Heavy Tank T26E3 chassis that had an extra bogie wheel per side as the 8in Gun Motor Carriage T93, but the war ended before they could be used and were later scrapped.

An 8-inch US Army field gun in action during the bombardment of Brest.

Transport

One of the requirements during development was that the gun be easy to emplace. Given the weight of the gun and carriage this was a challenge. Eventually, a pair of three-axle transport wagons were developed - one for the barrel/recoil mechanism and one for the carriage. These transport wagons were also used with the 240 mm howitzer. These were standardized as the M2 and M3. The six-wheeled wagon M2 carried the carriage and the M3 six wheeled transport carried the barrel and recoil system as shown below: This separate configuration required the use of the 20-ton M2 truck-mounted crane for set up. The crane included a clam-shell bucket that was transported on a trailer and used to dig the recoil pit for the gun. In spite of the weight and being transported in two pieces, the gun could be emplaced in two hours.^[4]

The transport wagons could be towed by heavy trucks; but, had problems in soft ground. The M6 High Speed Tractor which was designated for towing the 8 Inch Gun and 240mm Howitzer was not yet in product; so, the Ordinance Depart improvised. Obsolete M3 Lee medium tanks and depot storage M10 tank destroyer were quickly modified and tested. These proved to be satisfactory and were adopted for use as the M33 and M35 respectively.^[2]

Barrel of the M1 prepared for transportation, on display in the US Army Ordnance Museum

Variants

8in Gun Motor Carriage T93 - prototype

Service

The gun was assigned to non-divisional battalions that were under the control of GHQ Reserve. Eight battalions were organized trained and equipped. Each consisted of six guns organized into three batteries of two guns each. Five battalions were assigned to Europe (153rd, 243rd, 256th, 268th, and 575th) and three to the Pacific (570th, 573rd, and 780th).^[5] They first saw action in Italy in April 1944 at the Anzio beachhead when two guns were assigned to the 698th Field Artillery Battalion.^[6] Two guns also went to the Cassino front in Italy and were used in the counter-battery role against the German 170mm guns. They saw action in Europe where they were particularly effective against fortified targets and in counter-battery fire against German long-range artillery. At St. Malo France, two battalions of 8-inch guns participated in the siege. The 8-inch guns scored direct hits on the walls of the ancient citadel.^[7] In the Siegfried Line Campaign, the 8-inch guns, adjusted by aerial observers, knocked out two bridges over the Roer River.^[7] At the end of the war, the battalions were deactivated and the guns moved into storage; however, they were never again used in action and eventually disposed.

Seventeen guns were supplied to Great Britain.^[8]

Ammunition

The gun fired separate loading ammunition with two increments. M9 Green Bag propellant was used for medium ranges and was preferred for improved accuracy and reduced barrel erosion. M10 White Bag was used for long and extreme range firing. Only two fuses were used: M51A3 point detonating (and delay), and M67A3 mechanical time. Range and muzzle velocity below are for maximum charge of M10 White Bag.

Propelling Charges^[9]
Model	Weight	Components
M9	34.47 kg (76 lb)	Base charge and one increment
M10	48.12 kg (106.1 lb)	Base charge and one increment

Projectiles^[9]
Type	Model	Weight	Filler	Muzzle Velocity	Range
HE	HE M103 Shell	108.86 kg (240 lbs)	TNT, 9.52 kg (21 lbs)	868 m/s (2,850 ft/s)	32,584 m (35,635 yd)
Drill	Dummy M13	108.86 kg (240 lbs)

Existing Examples

Only three examples are known to have survived. They are located at:

45th Infantry Division Museum, Oklahoma City, OK
US Army Artillery Museum, Fort Sill, OK
US Army Ordinance Museum, Fort Lee, VA

References

↑ A Board of Officers (1919). The Report of the Westervelt Board. Morris Swett Library: The War Department. p. 30.
1 2 F., Schreier, Konrad (1994). Standard guide to U.S. World War II tanks & artillery. Krause Publications. p. 104. ISBN 0873412974. OCLC 31007442.
↑ Williford, Glen M. (2016). American breechloading mobile artillery 1875-1953 : an illustrated identification guide. Schiffer Publishing Ltd. p. 176. ISBN 9780764350498. OCLC 927401960.
↑ Steve., Zaloga, (2007). U S field artillery of World War II. Osprey Pub. p. 34. ISBN 9781846030611. OCLC 123895340.
↑ 1948-, Stanton, Shelby L., (1984). Order of battle, U.S. Army, World War II. Presidio. pp. 401, 404, 405, 414. ISBN 978-0891411956. OCLC 10727063.
↑ Williams, Captain Colin J. (July–August 2003). "Saved by Artillery: How MG Lucas Lost the Initiative at Anzio and the Allied Artillery Regained It". Field Artillery Journal – via Morris Swett Library Digital Collections & Archives.
1 2 Mayo, Lida (1991). The Ordnance Department: On Beachhead and Battlefron. Washington, DC: Center of Military History United States Army. pp. 266–267, 326.
↑ Steve., Zaloga, (2007). U S field artillery of World War II. Osprey Pub. p. 37. ISBN 9781846030611. OCLC 123895340.
1 2 Technical Manual TM9-1901 Artillery Ammunition. War Department. 1944. pp. 312–313, 206–207, 376.

Hogg, Ian V. (1998). Allied Artillery of World War Two. Greenhill Books. ISBN 1-85367-478-8.
Hogg, Ian V. The Guns, 1939-45. New York: Ballantine Books, 1970 ISBN 0019067100
Schreier Jr., Konrad F. – Standard guide to U.S. World War II Tanks & Artillery (1994) Krause Publications, ISBN 0-87341-297-4.
Williford, Glen M (2016). American Breechloading Mobile Artillery 1875-1953. Thomas D. Batha. Schiffer Publishing Ltd. ISBN 978-0-7643-5049-8.
Zaloga, Steven J. (2007). US Field Artillery of World War II. New Vanguard 131. illustrated by Brian Delf. Osprey Publishing. ISBN 978-1-84603-061-1.
Technical Manual TM9-2300 Standard Artillery and fire Control Material. (dated February 1944)
Technical Manual TM9-336 8-inch Gun M1 and Carriage M2. War Dept. Nov. 1943
Field Manual FM6-95 Service of the Piece 8-Inch Gun M! and 240-MM Howitzer M1. War Department. Feb 1946

External links

Wikimedia Commons has media related to 8in Gun M1.

British Artillery in World War II
United States. War Dept.. Service of the piece, 8-inch gun M1 and 240-MM howitzer M1.. Washington, D.C.. UNT Digital Library. Retrieved on 2012-08-17.

United States artillery of World War II
Tank guns	37 mm gun M5/M6 75 mm gun M2/M3/M6 76 mm gun M1 3 inch gun M7 90 mm gun M3 105 mm howitzer M4
Anti-tank guns	37 mm M3 57 mm M1 75 mm M1897 3 inch M5 90 mm T8 105mm T8
Field, medium and heavy guns	75 mm M1897 75 mm howitzer M1 105 mm howitzer M2 105 mm howitzer M3 4.5 inch gun M1 155 mm howitzer M1918 155 mm howitzer M1 155 mm gun M1918MI 155 mm gun M1/M2 "Long Tom" 8 inch howitzer M1/M2 8-inch gun M1 240 mm howitzer M1
Mortars	60 mm mortar M2 81 mm mortar M1 4.2 inch mortar M2 Little David
Other vehicle-mounted	75 mm howitzer M2/M3 75 mm gun M1897 105 mm howitzer M2 155 mm gun M1918MI 155 mm gun M2
Anti-aircraft guns	37 mm M1 40 mm M1 3-inch gun M1917 3 inch M3 90 mm M1 120 mm M1
Coast artillery guns	3-inch gun M1903 90 mm M1 6-inch gun M1903 155 mm gun M1918MI 8-inch Mk. VI 8-inch gun M1888 10-inch gun M1895 12-inch coast defense mortar 12-inch gun M1895 14-inch gun M1907 16-inch gun M1895 16-inch gun M1919 16-inch Marks 2 and 3 16-inch howitzer M1920
Railway artillery	8-inch Mk. VI 8-inch M1888 12-inch coast defense mortar 14-inch M1920

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