3 inch Gun M5

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3 inch Gun M5
M5 on carriage M6 on display at Fort Sam Houston, Texas.
Type	anti-tank gun
Place of origin	USA
Service history
In service	1943-
Used by	US Army
Wars	WWII
Production history
Produced	1942-1944
Number built	2,500
Specifications
Weight	combat: 2.21 t
Length	7.1 m
Barrel length	bore: 50 calibers
Width	2.2 m
Height	1.62
Shell	76.2x585R
Caliber	76.2 mm
Breech	horizontal block
Recoil	hydropneumatic
Carriage	split trail
Elevation	-5° to +30°
Traverse	45°
Rate of fire	12 rounds per minute
Maximum range	14.7 km

3 inch Gun M5 was an anti-tank gun developed in the United States during World War II, using a barrel of the 3-inch anti-aircraft gun T9 and elements of the 105 mm Howitzer M2. The gun was issued exclusively to the US Army tank destroyer battalions starting in 1943. It saw combat in the Italian Campaign and in the Northwest Europe. From early 1945 the gun was gradually removed from frontline service. However, as of 2005, it was still used by the US Army for ceremonial purposes.

Contents 1 Development and production history 2 Description 3 Service history 4 Ammunition 5 Notes 6 References 7 External links

[edit] Development and production history

Late in 1940 the US Ordnance Corps started a project to adapt the 3 inch anti-aircraft gun T9 to the anti-tank role. The barrel of the T9 was combined with breech, recoil system and carriage, all borrowed from the 105 mm howitzer M2.^[1] The pilot of the weapon, named 3 inch Gun T10, was ready by September 1941. Although the subsequent testing revealed minor problems, it was clear that the gun, eventually standardized as M5 on carriage M1, presents major performance improvement over existing designs.^[2]

Production began in December 1942. In November 1943 a slightly modified carriage was standardized as M6. In this carriage a flat shield borrowed from the 105 mm howitzer was replaced by a new sloped one. In January 1944 AGF requested to upgrade the guns built with the early carriage M1 to carriage M6; consequently most of the guns that reached the frontline had the M6 carriage.^[3]

Production of М5, pcs.[4]
Year	1942	1943	1944	Total
Produced, pcs.	250	1,250	1,000	2,500

[edit] Description

As stated above, the barrel was adapted from the 3 inch Gun T9; it had rifling with uniform right hand twist, with 28 grooves and one turn in 25 calibers. It was combined with breech, recoil system and carriage from the 105 mm Howitzer M2. The breech was of horizontal sliding type, manual; the recoil system hydropneumatic. The carriage was of split trail type, equipped with a single equilibrator spring beneath the breech and wheels with pneumatic tires.^[5]

[edit] Service history

External images
	3 inch Gun M5 on Carriage M1 [1]

Despite the performance advantages, it turned out that no branch of the US Army wanted the new gun. The Infantry considered it too large and heavy. The other possible user, the Tank Destroyer Center, preferred more mobile self-propelled weapons. Finally, a pressure from the head of Army Ground Forces, Gen. Lesley McNair, resulted in the gun being adopted by the TD Center. McNair's opinion was apparently influenced by the experience of the North African Campaign, where self-propelled guns were found to be hard to conceal.^[6]

On 31 March 1943 AGF ordered to convert fifteen self-propelled tank destroyer battalions to a towed form; eventually AGF decided that half of TD battalions should be towed. A towed TD battalion included three companies, each with three four-gun platoons, in total 36 pieces.^[7] M3 Halftracks were issued as prime movers. The organization from 1 September 1944 authorized M39 Armored Utility Vehicle instead, but these only reached frontline in spring 1945.^[8] Typically, a tank destroyer battalion was attached to an infantry division.^[9]

In October 1943 the first towed battalion - the 805th - arrived in Italy. Subsequently the M5 saw combat in the Italian Campaign and in the Northwest Europe.^[10]One of the most notable engagements came during the German counterattack on Mortain in August 1944. The 823rd TD battalion, attached to the 30th Infantry Division, played a key role in the successful defence of Saint Barthelemy, destroying 14 tanks and a number of other vehicles, though at the price of losing 11 of its guns.^[11]

In addition to the anti-tank role, the gun was often used to supplement divisional field artillery^[12] The gun could keep up a steady accurate fire when used as a support weapon; a combat report from the 614th TD mentioned a two-gun section firing 143 shells at enemy post in about 40 minutes and achieving 139 hits.^[13]

Although the M5 easily outperformed older anti-tank guns in the US service, it was large and heavy - making it hard to manhandle into position - and its anti-armor characteristics were found to be somewhat disappointing. In part that reputation reflected initial problems with fuses of APCBC/HE shells. It also must be noted that APDS round was never developed for the 3 inch gun;^[5] a 3 inch APCR round existed (see ammunition table below), but it is not clear if it was ever issued to towed TD battalions.

As a result of the aforementioned shortcomings, commanders and troops generally preferred an alternative in form of self-propelled tank destroyers, which offered better mobility and protection.^[14]

The greatest test of the TD battalions and their M5 guns came during the Battle of the Bulge. In this battle, towed tank destroyers fought much less successfully and suffered much higher losses than the self-propelled ones. A report from the aforementioned 823rd battalion said that "tank destroyer guns were one by one flanked by enemy tanks and personnel driven from guns by small arms and machine guns fire". Taking the recent combat experience into account, on 11 January 1945 the War Department confirmed a request to convert the towed TD battalions to the self-propelled form.^[15] This decision meant gradual removal of the M5 from frontline service, a process that continued until the end of the war in Europe.

As of 2005, the M5 was still used by the US Army for ceremonial purposes.

[edit] Ammunition

The M5 utilized fixed ammunition, with the same 76.2x585R cartridge case - designated 3-inch Cartridge Case Mk IIM2 - as other descendants of the 3-inch M1918 anti-aircraft gun.

Available ammunition[16][17]
Type	Model	Weight, kg (round/projectile)	Filler	Muzzle velocity, m/s
AP-T	AP M79 Shot	12.05 / 6.8	-	792
APCBC/HE-T	APC M62 Projectile	12.36 / 7		792
APCR-T	HVAP M93 Shot	9.42 / 4.26	-	1,036
HE	HE M42A1 Shell	11. 3 / 5.84	TNT, 390 g	853
Smoke	Smoke M88 Shell	6.99 / 3.35	Zinc chloride (HC)	274
Target practice	TP M85 Shot
Practice	Practice M42B2 Shell

 

Armor penetration table[16]
Ammunition \ Distance, m	457	914	1,371	1,828
AP M79 Shot (meet angle 30°, homogeneous armor)	109	92	76	64
APC M62 Projectile (meet angle 30°, homogeneous armor)	93	88	82	75
HVAP M93 Shot (meet angle 30°, homogeneous armor)	157	135	116	98
Different methods of armor penetration measurement were used in different countries / periods. Therefore, direct comparison is often impossible.

[edit] Notes

[edit] References

• Denny, Bryan E. (2003). The Evolution and Demise of U.S. Tank Destroyer Doctrine in the Second World War. Army Command and General Staff College, Fort Leavenworth, Kansas.  PDF copy
• Gabel, Christopher R. (1985). Seek, Strike and Destroy - US Army Tank Destroyer Doctrine in World War II, Leavenworth papers no. 12. Army Command and General Staff College, Fort Leavenworth, Kansas.  PDF copy
• Hogg, Ian V. (1998). Allied Artillery of World War Two. Crowood Press, Ramsbury. ISBN 1-86126-165-9. 
• Hunnicutt, R. P. (1992). Stuart: A History of the American Light Tank. Presidio Press. ISBN 0-89141-462-2. 
• Lee, Ulisses (1966). The Employment of Negro Troops. US Army Center of Military History.  Web link
• Zaloga, Steven J. (2005). US Anti-tank Artillery 1941-45, illustrated by Brian Delf, New Vanguard 107, Osprey Publishing. ISBN 1-84176-690-9. 
• Technical Manual TM 9-2005 volume 3, Infantry and Cavalry Accompanying Weapons, War Department, 1942.

[edit] External links

• Photo gallery at Kansas City Armor Modeling and Preservation Society website.

v • d • e 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 Field, Medium and Heavy guns 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 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 M3 · 90 mm M1 · 120 mm M1