Anti-tank Guns Usa Early Ww II (True Fact)

7/24/2019 Anti-tank Guns Usa Early Ww II (True Fact)

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USA Anti-Tank Guns (True Fact)

Various Notes-------------------------------------------------------

Anti-Tank Guns vsField Guns Cals Weight MV SW Rge y------------------------------------------------------------------37-mm M3 L/52 900 2,900 1.937-mm PAK-35/36 L/45 950 2,550 1.547-mm M1 [Mine] L/56.6 1,200 2,850 45-cm PaK-38 L/60 2,200 2,750 4.557-mm/6-pdr MK II, III L/43 2,500 2,800 6.357-mm/6-pdr MK IV V M1 L/50 2,500 2,950 6.357-mm M1 L/50 2,500 2,700 7.3Canon de 75 mle 1897 L/36 2,500 1,900 13.7 12,00075mm Field Gun M1917 L/30 2,900 1,850 15 13,50075mm Field Gun M1897A1 L/34.5 3,400 2,000 15 13,90075mm Field Gun M1897A4 L/34.5 3,400 2,000 15 13,90075mm Field Gun M1897A4 L/34.5 3,700 2,000 15 13,900

M2A3 Carriage75mm Field How M1A1 L/16 2,100 1,250 14.5 9,80075mm Pack Howitzer M1 L/16 1,400 1,250 14.5 9,8007.5-cm Pak-40 L/48 3,300 2,450 15

3-inch M5 L/50 4,900 2,600 1517pdr L/55 4,600 2,900 17105mm Howitzer M2 L/22.5 4,250 1,550 33 12,500

76.2mm Field Gun M1941 L/42 2,500 2,250 13.7 14,000 76/41, ZIS-376.2mm Field Gun M1943 L/42.6 2,500 2,250 13.7 14,500 76/43, SIS-3*85mm Field Gun M1943 L/55 3,750 2,600 21 18,00085mm Field Gun M1943 L/55 3,800 2,600 21 17,000 D44*

75mm Field Gun M1917 - Converted 18pdr76.2mm Field Gun M1943 SIS-3 - Numerous made. (*)85mm Field Gun M1943 D44 - numerous made/ (*)

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Tank Guns

Propellant and Shot Comparisons

Ammo Wt. MaxWeapon Ammo CR Pr Pj Br* MV Range37-mm M5 APC M51 3.4 ? 1.9 - 2,900 fps 800 yd

HE M63 2,600 fps 700 yd3.5 cals shorter than M6

37-mm M6 APC M51 3.4 ? 1.92 - 2,900 fps 800 ydHE M63 3.4 ? 1.61 ? 2,600 fps 700 ydHE M38 3.4 ? 1.24 ?Canister M2 3.4 ? 1.89

75-mm M2 AP M61 19.36 lb. [3] 2 lb [3] 14.5 lb 1,850 fps

HE @1 lb? [2] 14.6 lb 1.47 lb 1,450 fps75-mm M3 AP 2 lb [3] 15 lb 2,030 fps 14,000 yd

HE @1 lb? [2] 14.6 lb 1.47 lb 1,550 fps


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3-inch M5/M7 AP 2,600 fpsHE 2,800 fps 16,100 y

d76-mm M1 L/52 AP 3.6 lb [1]76-mm M1 L/52 AP

HE 12.37 lb .86 lb 2,800 14,780 yd17-pounder L/55 AP 9 lb [1]75-mm L/70 AP 8.1 lb [1]

MaxCR = Complete Round, Pr = Propellant, Pj= Projectile*, Br = Bursting Charge

ChamberWeapon Pressure Weight RPM75-mm M2 36,000 783 lb. [3] 2075-mm M3 38,000 910 lb. [2] 203-inch M5/M7 1,990 lb [2] 5,000 lb.76-mm M1 L/52 38,000 [1]76-mm M1 L/52 43,000 [2] 1,204 lb [2]17-pounder L/55 48,000 1800, 4700 complete MK I75-mm L/70 48,000

[1] M4 76mm Sherman-Medium Tank-Osprey-NV-073. pp. 4, 5.[2] 75mm M3 gun, 76-mm M1, 3-inch M7 (leaflet?)[3] 75-mm Tank Gun M2 FM23-95

Length Length OverallTube Overall Weight Cals

37-mm Gun M6 L/50 72.85" 77.35" 185 lb 50 / 5375-mm Gun M2 L/28.5 84" 91.75 783 lb75-mm Gun M3 L/37.5 110.625" 118.375 910 lb

26.625 26.625 127 lb4.77 lb per inch

3-inch Gun M7 L/50 150" 158.1" 1,990 lb76-mm Gun M1 L/52 156" 168" 1,207 lb 904 lb

45.375 49.625 +216 lb90-mm Gun M3 L/50 177.25" 195" 2,410 lb90-mm Gun M3 L/50 177.25" 195" 2,260 lb

1,465 lb75-mm How M1 L/15.9 47" 342 lb

75-mm M1879A4 L/34.5 101.87 1,035 lb 440 lb

105-mm How M3 L/16 995 lb105-mm How M4 L/22 [c. 1,400 lb]105-mm How M2 Tube & breech (1,100)

Gain of 130 pounds for L/28.5 to L/37.5 = 130 / 9 = 14.44 lb/cal= 127 / 9 = 14.11 per cal

From L/37.5 to L/52 = 14.5 x 14.44 = 209 lb = 14.5 x 14.11 = 205 lb

bold underline emphasis

Length Length Overall TubeTube Overall Weight Weight Cals


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6-pdr Mk 3 L/43 96.2 7686-pdr Mk 5 L/50 112.2 72075-mm QF MK V and MK VA L/36.5 (1) 107.8 112.576 69277-mm QF Mk II L/49 147.65 165.5 15023-inch Howitzer QF MK1, Mk1A L/25 75 78.2 25695-mm Tank How QF Mk-1 L/21 80.4 85.52 8673.7in Mortar (How) Ord QF Mk 1 L/15 55.5 59.2 22217-pounder Mk VII L/55 165.45 172.25 1885 203217-pounder Mk IV 165.45 184.03 1800, 4700 complete MK I17-pounder Mk VI 165.45 183.817-pounder Mk VII 165.45 184.05

(1) Based on the 6-pounder increased to 75-mm caliber.

#### THE USA ANTI-TANK GUN WAS DESIGNED BEFORE IT WAS MOUNTED ON THE M2 tank ####

Late 1920s Infantry developed a 37-mm gun they adopted.

37-mm Anti-Tank Gun M2A1******************************

Characteristics generally unknown.Obsoleted in 1932 due to service tests where both the Artillery and Infantry considered them Obsolete.Version of the 37-mm M1916 with sliding breech block in place of 75-mm 1897 style concentric screw.Only 37-mm M1916 trench gun left once it was obsoleted.

Tests leading up to 37-mm******************************Hotchkiss 25-mm in 1935.Dec. 1935 reports from Europe concerning Rhienmetal Pak offered for trials and purchasing. Decided to request one for trials.1936 study of anti-mechanization weapons.

Sep. 1937 "Hurry up, everyone else has an AT and intermediate AA guns, and we don't." message from Chief of Staff to Ordnance.

47-mm Gun (Unknown if ever assigned a mark number or test type)******************************1936 created as a scaled up Pak-37. Hunnicut indicates it was a revised 37-mm M1AA gun, not PaK which the ordnance Department likely did not have access to.Tested on M2A1 light tank hull in an open mount of mild steel as a motorized gunfor combating anti-tank guns, and secondly as an anti-tank gun.Did not perform well and never accepted.No other details on the cannon.

Spanish Civil War

******************************17 July 1936 to 1 April 19391936-1939 Spanish Civil War. Various lessons about tanks and anti-tank guns garnered.(1) Anti-tank guns like German 37-mm and Soviet 45-mm rose to a threat to tanks.(2) More armor was needed.U.S. could afford a cannon for the M2 but not a redesign for more armor. The M2hull and suspension would require major changes to handle any significant increase in weight - a tank redesign as it were.


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Chiefs of Ordnance***********************************Four chiefs of Ordnance served the Department during the years between world wars: General Williams, 191830; Maj. Gen. Samuel Hof, 193034; Maj. Gen. William H. Tschappat, 193438; and Maj. Gen. Charles M. Wesson, 193842, General [Clarence C.] Williams, an officer whose conception of the Ordnance mission had been profoundlyaffected by his overseas service in 191718, combined open-mindedness with unusualadministrative ability. His vigorous pursuit of the Westervelt Board recommendations on new equipment, his encouragement of industrial mobilization planning, and his judicious selection of officers to carry out these basic policies earnedhim universal respect.

Ordnance Department; Planning Munitions for War CMH_Pub_10-9

37-mm Anti-Tank Gun M3, Tank Gun M5, M6***********************************M3 Lee Medium AFVDB: "The differences in the 37mm and 75mm guns are as follows:The 37mm gun M5 was 6" (15cm) shorter than the M6, and the M5 had a manually-operated breechblock instead of the M6's semiautomatic breechblock. The 75mm gun M2had a shorter barrel than the M3 and had a vertical breechblock to the M3's horizontal breechblock. Otherwise, the 75mm guns were identical."

January 1937 ordnance Department authorized to develop a new 37-mm gun and a Rhe

inmetall 37-mm PaK was acquired for comparisons.Pilot models authorized Sept. 9 1937 as 37-mm Gun T3 and Gun Carriage T1.Trials at APG February and March 1938 uncovered numerous flaws: weak ammunition,bad design of the breech, and wobbly carriage.Went through 4 more designs for both bringing the carriage to T5.August 1938 War Department remanded ordnance Department for suggesting the use of a 45-mm or 47-mm gun instead. and said no funding for work on a larger caliberweapon was coming forth in 1939 or 1940.Summer 1938 trials led to the acceptance of the 37-mm Gun T10 on carriage T5 asthe 37-mm Gun M3 and Carriage M4 on December 15, 1938.

"The American gun was designed for use not only on tanks but also as a light field gun mounted on its own carriage, adapted to towing either by truck or tractor

or by its crew of four men. Hence the Infantry was insistent that the weight ofgun and carriage together must not exceed 1,000 pounds. This weight limit precluded a gun of larger caliber. The gun itself was basically one and the same whether mounted on a carriage or in a tank, but because the gun when mounted in a tank had to be shortened six inches, it was re-designated the 37-mm. M5, and later, with a change in the breech mechanism, the M6. The antitank gun M3, for mounting upon the carriage M4, kept a hand-operated breech mechanism. This gun was 6 feet 10.5 inches long, weighed 191 pounds, had a muzzle velocity of 2,600 feet per second, a range of about 12,000 yards, and could fire 25 rounds a minute. Ordnance engineers expended only less effort upon the carriage than upon the gun, inasmuch as the traverse, elevating mechanism, and locking devices were fixed to the carriage. [47] The requirement for ammunition was armor-piercing shot capableof penetrating 1.5 inches of armor on impact 20 degrees from normal at a range

of 1,000 yards. By 1938 armor-piercing shot M51 was standardized with tracer, and later also a high-explosive shell with the M38A1 base detonating fuze. [48]

Thus, some four years were devoted to development of the U.S. Army's first antitank gun which, in terms of what the Soviet Union and Germany had readyby 1939, was obsolete before it was standardized. From a military observer in Europe word had come of developments in Germany, and observers in Spain during theSpanish Civil War had opportunity to note the outstanding performance of the Russian 45-mm. antitank gun. Yet the decision to push the 37-mm. was not rescinded. In August 1938, before the Ordnance Department had proceeded far with procurement, the War Department issued explicit instructions to the Chief of Ordnance:


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1. The Infantry is designated as the most interested using arm for the 37-mm antitank gun under AR 850-25.2. No development funds will be expended by the Ordnance Department during the Fiscal Years 1939 or 1940 in the development of antimechanized weapons of largerthan 37-mm caliber. If the necessity for an antitank gun of larger than 37-mm caliber develops, the arm responsible for its development will be designated at that time.49This decision of the General Staff, closing the door to alternative design, wasdeplored by many Ordnance officers. The chief of the Artillery Branch of the Manufacturing Division from 1937 to 1939 later stated:

The Ordnance Department was well aware that the 37-mm gun was totally inadequateas an antitank gun, and many and repeated efforts were made to convince the various interested using services personnel of this fact.The Infantry personnel were very much impressed with the compact design of the Rheinmetall 37 and at one time in fact demanded a duplicate. The deciding criterion was the overall weight ... 850 pounds.Page 185This was considered the maximum that four men could comfortably wheel over the ground.It is my opinion that all of the early artillery of World War II ... suffered from the continued insistence by the using arms on mobility even at the expense ofstriking power.50

This testimony leads to the conclusion that General Williamsscheme of allowing the using arms to have the final say about types of equipment had been carried toan extreme where Ordnance experts could no longer greatly influence important decisions.

Ordnance Department; Planning Munitions for War CMH_Pub_10-9

December 1938 Field Artillery proposed "... a truck-drawn weapon weighing about1,500 pounds with a muzzle velocity sufficient to penetrate 2.5-inch armor at impact 20 degrees from normal [68-mm/2.7-inches; 67.6-mm/2.66-inches] at a range of 1,000 yards. But the Chief of Ordnance objected that the introduction of an additional weapon with new types of ammunition would complicate production and supply, that the 75-mm. howitzer and 75-mm. field gun effectively supplemented the

37-mm. as antitank weapons, and that the gun requested by the Field Artillery could not weigh less than 2,700 pounds. The Field Artillery withdrew its request.[51]

Sixteen months later the Chief of Staff reviewed the question. "It occurs to me," wrote General Marshall in June 1940, "that we should initiate development of a heavier caliber antitank gun than the 37-mm. Reports from abroad indicate that the 37-mm. has been found comparatively ineffective against the heaviertype tank armor and that a 47-mm. gun (possibly on a self-propelled mount) maybe necessary as an arm for corps and division antiaircraft battalions." [52]

"General Wesson's [Chief of Ordnance] reply evinced no corresponding anxiety. He repeated the substance of his earlier statement that for its weight the37-mm. antitank gun was very effective; it would penetrate the armor on American light and medium tanks. The 47-mm. a study of which had been conducted in 1939

, was not enough more powerful than the 37-mm. to justify development. At leasta 57-mm. would be needed, and in view of the existence of the 75-mm. field gun,work on a 57-mm. seemed uncalled for. The 37-mm. supplemented by the 75-mm. witharmor-piercing ammunition appeared to be adequate, though perhaps a more powerful gun might be needed to combat heavy tanks. [53] In conclusion he declared that the best way to supply self-propelled antitank artillery was to mount antitankguns on tanks."

[Ordnance Procurement and Supply CMH Pub 10-10, pg. 81:]Production: Started with M5 Tank Guns. Watervliet received the first production


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contracts: they had the tools needed to make them since they were the lead whenthe gun was being developed and had manufactured the pilot guns.

November 1938: 18 gun orderJune 1939: About 400 more ordered.Feb. 1940 shipped the first 18. Thereafter began producing 150 per month

starting Early 1941.Summer 1940: 2 more companies began producing: National Pneumatic Compan

y and United Shoe Machinery Corporation, producing 2,800 and switched to M6s after Pearl Harbor.

American Type Founders contracted to build M6s late 1940 supplying around 900 before 1941 ended.

Thus roughly 5,000 provided by the arsenal and 3 civilian contractors atthe finish of 1941 and yet orders were for 35,000 (including so many thousand for the British).

Ant-Tank Gun M3: Starting Winter 1939-1940.Watervliet built guns, Rock Island carriages.April 1940 York Safe and Lock Company given contracts for guns and carri

ages. Several weeks later United Shoe Machinery Corporation and National Pneumatic Company built guns while Muncie Gear Works and Duplex Printing Press Company built carriages.

Slow ramp-up from signing on to getting into production led to the G4'sconclusion: "Delivery of 37-mm. AT guns is very slow, and it will be at least 18

months before the requirements for existing units will be filled."

Table 9: Artillery Production,. 1 July 194031 December 1941 (select entries)-------------------37-mm. gun, AT 2,59237-mm. gun, AA 50437-mm. gun, tank 5,57137-mm. gun, aircraft 390

#####################################

57-mm Anti-Tank Gun M1

-------------------------------------------------------British completed the 6-pdr Mk. I in 1939.

February 1941. Chief of Ordnance started the process needed to begin manufacturing the British 6-pounder. February 1942 the USA 57-mm M1 Anti-Tank gun first produced.

The Army had no plans to adopt it but most people saw it as a need for supplyingthe British Lend Lease. The U.S. received one of the long barreld MK Is and hence (having adeuqate lathes) built them L/50.

November 1941 British began building their own 6-pounder. Production began withthe shorter barreled Mk. II due to lack of lathes for the longer barrel. [US Ant

i Tank Artillery 1941-45; Zaloga; Osprey; 2005]

February 1942 the USA 57-mm M1 Anti-Tank gun first produced. Retained the British side-shields throughout service.

The 37-mm proved poor in Tunisia and as such the Infantry Command decided to replace it with the 57-mm. Accepted in Service May 1943, although it seems some were in oran in April 1943. Some units had switched over by the invasion of Scicily(Patton's 3rd Army was critical of the lack of HE rounds as HE targets were quiet common).


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"The adoption of the British 57mm gun made the most sense as it was already in production in the United States. Ordnance felt it was the wrong move, since the 57mm gun would be obsolete by the time it reached service. The Ordnance viewpointwas ignored, however..." [US Anti Tank Artillery 1941-45; Zaloga; Osprey; 2005pg 14]

Although the 1.5 ton truck was assigned the prime mover the halftrack was oftenused instead, although during the Battle of the Bulge one officer complained ofhaving issues moving guns by truck.

Various detail changes were made throughout the life of the gun: U.S. Army trucks required a different lunette assembly to tow them (M1A3 carriage; M1A2 was themodel for Lend Lease as the British had no requirement for the change); casterwheel to aide in swinging the trail; etc..

Experiments included the British Molins Automatic Loader Mk. I and T10 57/40mm squeeze bore adaptor which failed.

U.S. Organization3 each battalion = 9 (anti-tank platoons)3 anti-tank companies with 3 each = 9total: 18 per regiment

3 regiments per division = 54 per division

[US Anti Tank Artillery 1941-45; Zaloga; Osprey; 2005 pg 15]

The U.S. had not planned to adopt the 57-mm and as such had not set up asystem for manufacturing any ammunition except Armor Piercing. Manufacture of other rounds lagged: the high explosive T18 became M303 authorized March 1944 butnone shipped until after the Normandy campaign; the T17 adopted as M305 canister was tested in April 1944 but not produced until January 1945 and as such little if any reached Europe in time for combat use. This hindering the 57-mm in thefield gun role. Some U.S. units acquired HE rounds from the British.

The U.S. never developed a HVAP round for the 57-mm although (again) som

e U.S. units acquired APDS rounds from the British. This was so common that somecommanding officers included it as part of the regular ammunition loads. The lack of a U.S. tungsten shot convinced some U.S. 57-mm gunners that the British 6-pdr. was more effective for some magical reason. They were in fact the same basic cannon. If anything, early British 6-pdrs. had a shorter barrel (L/43) that the 57 or later 6 pdrs. (L/50) due to an initial shortage of lathes needed for thelonger barrels. Which would mean that at one time U.S. 57s were more powerful than British 6 pdrs.

This confusion sometimes occurred because U.S. Airborne units found the57-mm to be too heavy and rejected it at first. But then accepted the British "Airborne" model with narrower wheels and other modifications that made it easierto load into gliders.

This confusion sometimes occurred because U.S. Airborne units found the

57-mm to be too heavy and rejected it at first. But then accepted the British "Airborne" model with narrower wheels and other modifications that made it easierto load into gliders.

The British adopted a muzzle brake later but the U.S. did not seem to (although paratroopers with British airborne guns can be seen with muzzle brakes).

Standard Guide to U.S. World War II TANKS & ARTILLERY indicates it "bucked" (hopped) a bit and illustrates a 57-mm in recoil with the wheels a few inches off the ground. Some other cannon like the 105-mm M3 also jumped under variousconditions. (Sabot Work by University of New Mexico).


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British Experience With 6 pounder----------------

The original pilot had a long barrel (L/50). Due to a lack of lathes tobuild long barrels the MK II/III (anti-tank/tank) models were 43 calibers long (L/43) (760 lb. - 770lb.). They were also heavy due to the straight pug-nosed barrel. Velocity was around 100 fs. slower than the L/50 (anti-tank/tank). The longer barreled weapon (L/50) MK IV/V not only had more velocity but was actually lighter due to slender barrel contours and other weight saving changes (730 lb.).The author has seen U.S. manufactured "guns" stamped 725 lb. and in all likelihood actual produced weapons varied in weight.

The British had issues fighting German tanks in 1942 because of the useof face hardened plate for the frontal armor of the Pzkw III and IV. The 2-pdr.had grown ineffective except against the engine grills and other side or rear weak spots. The 6-pounder could not handle the frontal armor but was dandy againstthe sides and rear. [El Alamein: The Battle that Turned the Tide of the SecondWorld War; Hammond; Osprey; 2012] notes the deficiencies against frontal armor during the the El Alamein campaign July - November 1942 while [El Alamein 1942: Battle Story; Battistelli; Spellmount; 2011] noted that the 6pdr. was only effective to around 1,000 meters/1100 yd. while the 75-mm on the Grant/Lee and Shermanwas effective to 2,000 meters/2,200 yds. likely for this reason.

Ordnance Department; Planning Munitions for War CMH_Pub_10-9 pg. 73 note: "American 75-mm. APC ammunition, though then made without an explosive charge,was credited with saving the day in Libya, as British uncapped ammunition was i

neffective against German face-hardened plate"

[http://www.wwiiequipment.com/index.php?option=com_content&view=article&id=74:6-pounder-anti-tank-gun&catid=40:anti-tank&Itemid=58]

The initial loadings used a 6.28 lb. plain AP (uncapped) round at 2,650fs. later increased to 2,800/2,900 fs.

The 6-pdr was hampered by a lack of capped shot which was first producedby the British in 1943 in uncapped form. In 1943 the APCBC shot was introducedweighing 7.11-7.13 lb. with a velocity of 2630/2780 fs. which may have been theunfilled equivilent of the U.S. APCBC shot 7.28 lb. [Artillery Ammunition TM9-1901 June 1944]

U.S. APC shot was always "APCBC" and hence the "APCBC" was not specifiedin U.S. parlance.

1941 1942 1943 1944 1945AP 160,000 6,150,000 7,130,000 - -AP(o) - 1,838,000 1,330,000 30,000APC - - 534,000 - -APCBC - - 1,125,000 1,143,000APCBC(o)- - 430,000 2,044,000APDS - - - 217,000 158,000HE NF 396,000 1,865,000 286,000 172,000

57-mm Gun on Carriage T2-------------------------------------------------------"The US Army felt that the 6-pdr carriage wasn't stable enough and recommended that a domestic design be initiated in May 1941. This was eventually approved asthe 57mm gun T2 and carriage T1. Four pilots were constructed, two based aroundthe hydropneumatic recoil mechanism of the 75mm pack howitzer, and two with hydrospring recuperators. The T2 gun used the same 57mm ammunition as the British. Testing of the designs began in the spring of 1942, and comparative trials were conducted with the American-manufactured 57mm (6-pdr) in the summer. Although thenew American carriage design was generally more stable than the original Britis


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h design, there was still no US Army requirement for a towed 57mm anti-tank gun;it was therefore difficult to justify production of the weapon, as the gun hadthe same ballistic performance as its British counterpart. The project was keptopen and many improvements incorporated into the design, but it proved to be a waste of effort."[US Anti Tank Artillery 1941-45; Zaloga; Osprey; 2005 pg 14]#####################################

75-mm Howitzer

"75-mm. Pack Howitzer

The 75-mm. pack howitzer belongs to the specialized group of weapons assigned for use in mountainous country where motorized or horse-drawn artillery cannot go. Easy disassembly for packing on mule-back is essential. Before World WarI the Ordnance Department had spent a good deal of effort designing a mountaingun better than the English Vickers-Maxim 2.95-inch then in use, but the projectwas dropped when it was apparent that the AEF would have no use for mountain guns. In 1919 the Westervelt Board, reviving the project pronounced a pack howitzer to be "one of the items of artillery in most urgent need of development." [35]The ideal weapon should have a caliber of about 3 inches, possible elevation of45 degrees, a minimum range of at least 5,000 yards, and should be capable of being packed in four separate loads of about 225 pounds each. A first postwar model, the M1920 which incorporated these features, was soon found unsatisfactory,

chiefly because recuperator, piston rod, and trail were inadequate. [36] The next six years saw intensive work on models designed to correct these weaknesses and to furnish a mountain gun at least as powerful as new foreign types. Greater range was particularly desired. The weapon standardized in 1927 as the 75-mm. Pack Howitzer M1 had a range of 9,200 yards and weighed 1,269 pounds in firing position. It took rank as one of the most efficient artillery weapons yet devised. [37] The Chief of Field Artillery asserted: "It is a remarkable weapon with a great future .... In its adaptability under pack it has exceeded any expectations which could reasonably have been held considering the power of the weapon." [38]Some modifications, chiefly of the recoil mechanism, and a new carriage were completed during the thirties.

But in spite of faith in the usefulness of this weapon, only thirty-two p

ack howitzers had been manufactured by 1 July 1940. [39]"

Ordnance Department; Planning Munitions for War CMH_Pub_10-9, pp. 180-

#######################################

--------------------------------------75-mm 1897 Guns

[75-mm Gun Material M1897 And Modifications; TM9 305; 1941; U.S. Army TechnicalManual]

75-mm guns Weight (pounds)M1897 1,015M1897A2 1,035M1897A3 1,035M1897A4 1,035

Carriage Weight Elevation Depression Traverse R LM1897 2657 19 10 3/3Original FrenchM1897M1A2 2657 19 10 3/3


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French made in U.S.A.M1897A4 3007 19 10 3/3High Speed.M2A1 3447 46 10 45/40M2A2 3447 46 10 45/40M2A3 3225 45-30' 10-30' 3/3

--------------------------------------75-mm Anti-Tank Gun on Carriage M2A1 [Fact].This gun threw the author at first because there was no "mark number" until he realized it was in essence the first 75-mm anti-tank gun the US Army adopted. Andjust as interesting, it was usually not referred to as such: rather, technicalmanuals refer to it as the 75-mm Gun 1897 Gun on Carriage M2A1.

In 1939 and 1940 the realities of war shook up the General stuff who broke down and accepted the fact that the 37-mm was a pitiful gun to force on US troops. It was then that the building of a tank with a 75-mm gun was allowed. (InJune 1940).

--------------------------------------75-mm Anti-Tank Gun on Carriage M2A1 [Fact].

The Ordnance Department suggested mounting 1897 guns on the new M2A1 split trail carriage designed for the 105-mm howitzer with a shield and direct firesight as an interim heavy antitank gun. Production began in July 1940 and by November 1941 exactly 918 had been converted. The use of the 105 carriage almost g

uaranteed this was a heavy bitch of a gun (3,700 pounds per Ian Hoggs Allied Artillery of World War Two; The Crowood Press; 1998), as shown by the mounting of the 3-inch gun T9 on the same basic carriage.

[3-inch T9 + 105-mm breech = 1,800 lb.; 75-mm 1897 tube + breech = 1,000lb.; 3,700 + 800 lb. difference = 4,500 lb. for the 3-inch M5 ATG].

[75-mm Gun Material M1897 And Modifications; TM9 305; 1941; U.S. Army Technical Manual] gives weight of 3,200 lb.

Rejection of a 75-mm armed tank...-------"If that was truth, not flattery, the lead was lost in 1938. In spite of a report from Berlin describing the German experimental mounting of an 88-mm. gun in a

tank, the Chief of Infantry declared so powerful a weapon as a 75-mm, needless.107 As a result of this judgment, the pilots of the M2 and M2A1 medium tanks, built the next year, were each armed only with a 37-mm. gun, eight .30-caliber machine guns, and a .45-caliber submachine gun. Meanwhile, the mechanized Cavalry was clamoring for a self-propelled cannon to neutralize enemy antitank guns. Onlywhen the War Department conceded that a 75-mm. howitzer mounted on a combat carchassis* was virtually a tank was a new decision reached; approval of designinga tank equipped with a 75-mm. howitzer came at last in July 1940. The Armored Force, headed by a Cavalry officer, Brig. Gen. Adna R. Chaffee, was established that month.108"

[Ordnance Procurement and Supply CMH Pub 10-10, 201]

* T3 75-mm Howitzer Experiment?

--------------------------------------75-mm Tank Gun M2, M3 [Pure Fact]75-mm M2, 75-mm M3

M3 Lee Medium AFVDB: "The differences in the 37mm and 75mm guns are as follows:The 37mm gun M5 was 6" (15cm) shorter than the M6, and the M5 had a manually-operated breechblock instead of the M6's semiautomatic breechblock. The 75mm gun M2had a shorter barrel than the M3 and had a vertical breechblock to the M3's hor


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izontal breechblock. Otherwise, the 75mm guns were identical."

The exact reasons behind the choices that led to the 75-mm Tank Gun M2 and M3 have never been given, but it seems obvious that in 1941 when the 75-mm armed tank was finally given the go-ahead the Army wanted a "75" as fast as possible; they did not want a new ammunition type; the 1897 model 75s were old and still needed; and the only modernized design was the pre-production T5 anti-aircraft gun tube.

Hunnicut says the 75 was seen as "artillery" not an AT gun and the AP shot was an afterthought.

The first envisioned tank was the M3 with a 37-mm anti-tank gun and the75-mm as a field gun.

[Where did I get the T5 info?] From brief snatches of information it seems the T5 was designed to continue the 75-mm 1897 line of anti-aircraft guns butit fired the mid-velocity 1897 cartridge which was simply no longer useful against the higher flying aircraft of the 1930s and 1940s.

Hunnicut notes that the 75mm T6 was an anti-aircraft gun standardized asthe 75-mm Tank Gun M2 used in a test to develop an mobile AA gun based on the M3 chassis as the 75-mm Gun motor Carriage T26, with work initiated in an October1941 Ordnance Committee project but ending in March 1942 after the mid-velocitynature of the 75 was determined unsuited for such use. [Sherman, pg. 387] [Wasthis the 75-mm Tank Gun M1?] The T7/M2 was based on it and had the same 84" borelength.

Hunnicut notes that they tested a 71.25 inch long bore but extreme amoun

t of muzzle blast resulted.According to the "Illustrated Directory of Tanks of The World" by DavidMiller (Salamander; 2000) in September 1940 the Armored Force requested higher velocities from the 75 (assumingly higher than the T7/M2).

There was a 75-mm T6 and then a 75-mm T7 which became the M2 gun (1,850f/s in 1942; 1930 f/s by 1944) in May 1941. In June 1941 the T8 became the longer barreled 75-mm M3 (2,030 f/s).

75-mm M2 AP M61 19.36 lb. [3] 2 lb [3] 14.5 lb 1,850 fps

HE @1 lb? [2] 14.6 lb 1.47 lb 1,450 fps75-mm M3 AP 2 lb [3] 15 lb 2,030 fp

s

Mounting 37-mm in turret and 75-mm in hull to create the M3 medium tank... "

FM23-95 75-mm Tank Gun M2 (Mounted on Medium Tank M3) May 1942 gives a velocityof 1,850 fs. for armor piercing shot. Base Penentration: 70-mm/2.8in@30;81-mm/3.2in@0

TM9-1901 Artillery Ammunition June 1944 Gives a velocity of 1,930 fs. for the M2gun with armor piercing shot. Base Penetration: 74-mm/2.9in@30;85-mm/3.3in@0Velocity for the M3 gun is always quoted as 2,030 fs. Base Penetration: 77-mm/3in@30;89-mm/3.5in@0Other than those with dyslexia who give "2300 fs." and those who round up to "20

50 fs." or down to "2000 fs."Armor penentrating ballistics favor 2000 fs. for the M3. Base Penetration: 76-mm/3in@30;88-mm/3.5in@0

M2 GUN 1,850 fs. 70-mm/2.8in@30;81-mm/3.2in@0 FM23-95M2 GUN 1,930 fs. 74-mm/2.9in@30;85-mm/3.3in@0 TM9-1901M3 GUN 2,030 fs. 77-mm/3.0in@30;89-mm/3.5in@0 TM9-1901

FM23-95 75-mm Tank Gun M2 (Mounted on Medium Tank M3) May 1942TM9-1901 Artillery Ammunition June 1944


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Armor penetrating ballistics favor 2000 fs. for the M3. Base Penentration: 76-mm/3in@30;88-mm/3.5in@0

Penetration quotes from TM9-1901 for the M2, M3, and 1897 guns are:75-mm APC M61A1 3.4" @ 0 @ 1,000 yd FH M3 Gun

2.8" @ 0 @ 1,000 yd RH75-mm APC M61A1 3.1" @ 0 @ 1,000 yd FH M2, M1916, M1917

2.6" @ 0 @ 1,000 yd RH75-mm APC M61A1 3.3" @ 0 @ 1,000 yd FH M1897A4

2.7" @ 0 @ 1,000 yd RH

(FH = Face Hardened, Rh = Rolled Homogenous)

"Although a makeshift, this arrangement was hailed in 1940 as the only available answer to the threat of German armor, and by September demands for 75-mm. tank guns reached the 2,500 mark.

"An order for 1,308 75-mm. tank guns was assigned to Watervliet in mid-July 1940, and 9 months later the first completed units were shipped. By September 1941 Watervliet was turning out 75-mm's. at the rate of one hundred per month,and had completed nearly one thousand by the end of the year. Meanwhile, as requirements continued to rise, two commercial firms were given contracts in Augustand September of 1940, the Empire Ordnance Corporation of Philadelphia and the

Cowdrey Machine Works of Fitchburg, Mass. {62} Both were slow to get into production, and neither was regarded as a strong source. {63} Empire shipped its firstguns in August 1941 and Cowdrey in January 1942. Just a week before Pearl Harbor, with total requirements rising above twenty thousand and guns lagging behindtank production, a third source was added, the Oldsmobile Division of General Motors Corporation. Watervliet carried the burden of production during the critical months of the emergency period, manufacturing 1,000 of the 1,200 guns producedduring 1941. {64}""[Ordnance Procurement and Supply CMH Pub 10-10, 82-83]

"The M2 was standardized in May 1941 and the M3 in June 1941." (Footnote on page83, Ordnance Procurement and Supply CMH Pub 10-10)

Table 9: Artillery Production,. 1 July 194031 December 1941 (select entries)------------75-mm. gun, AT 918 [918 1897 field guns fit to howitzer carriage M2]75-mm. gun, tank 1,21675-mm. howitzer 4583-inch gun, field 140 [3-inch AT guns? Prototypes?]

#######################################75-mm M4 Aerial Cannon

Ordnance Department; Planning Munitions for War CMH_Pub_10-9, pgs. 441, 442NOTE: Lightweight steels used 1944.

"Meanwhile, long before work on the M9 37-mm. cannon began, Ordnance engineers had been trying to develop a still more powerful strafing weapon. The 75-mm. field gun tested in plane-to-plane fire in the summer of 1940 had established the feasibility of mounting a big gun in aircraft. Though further work on that first development project had lapsed, the Air Corps had evinced some interest in a scheme to install a 75-mm. in a plane built to mount it for fire against ground targets. In mid-1941 the Douglas Aircraft Company, instead of using the B-18 first t


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ried, undertook to adapt a new medium bomber to take a specially designed cannonand mount. Though a Douglas XA26B did mount a 75 and fire it successfully in June 1942, the bomber that eventually carried the 75-mm. into action was the B-25made by the North American Aviation Corporation. In 1941 Ordnance engineers to whom design of the gun, mount, and fire control system was assigned had for guidance only the knowledge that the job was possible. It meant a completely fresh start, for the field gun tried as an air-to-air weapon could not readily be modified to meet the new requirements for air-to-ground fire. In one respect only wasthe designerstask simplified: impact fuzes and aiming by ordinary gun sights would suffice for effective strafing of stationary or slow-moving ground targets, whereas proximity fuzes or preset fuzes and elaborate range finders would have been needed against aerial targets.2 Still the problems were peculiarly difficult.

The 44-inch recoil mechanism of the ground-mounted gun was impossible to use inthe confined space of a plane. Shortened recoil would increase trunnion reaction, and mounting the conventional hydromatic recoil and counterrecoil cylinders above or below the gun tube would make the gun silhouette too large, Ordnance engineers found the answer in step-by-step modification of the 75-mm, M3 tank gun and in development of a new mount. The single-shot, hand-loaded weapon with its vertical sliding, automaticallyoperated breechblock was fired electrically. An ejector mechanism spewed out the shell case after the round was fired. A hydro-spring recoil mechanism using two cylinders mounted above and below the gun barrel reduced the silhouette somewhat. The stronger construction of the newer bombers enabled Ordnance engineers to let the plane absorb part of the recoil shock and t

hus limit the recoil stroke to the 21-inch length of the round, a space needed in any case to load the gun. In the first models an automatically functioning muzzle cover that opened when the breech was closed and closed when the breech opened was provided to prevent fumes from pouring into the gunners compartment afterfiring and to ease ammunition loading, but this feature was found unnecessary and later dropped.

Page 442

The model accepted in the summer of 1942 was designated the 75-mm. aircraft gunM4, and its mount the M6. Gun and mount together weighed 893 pounds. Muzzle velocity with high-explosive ammunition averaged 1,974 feet per second, with armor-piercing-capped ammunition, 2,024.3 The ammunition was the same as that standard

for ground guns, a considerable advantage in procurement. Moreover, on at leastone occasion, this interchangeability was of importance in the field. Maj. Gen,Claire L. Chennault in his memoirs described how one of his officers saved the day for Chinese troops equipped with three old French 75-mm. field guns but no ammunition. Sacrificing some of his cherished supply of 75-mm. aircraft shell, thepilot dropped enough to the Chinese to put their guns into action. From the Pacific theatres after 1942 came testimony to the effectiveness of the gun for strafing. Its fire destroyed pillboxes and sank naval vessels. In July 1943, for example, two B-25 bombers mounting 75-mm. air cannon attacked a large Japanese destroyer off the coast of Cape Gloucester and in two runs, firing seven shots on each run, riddled the ship from stem to stern and left it sinking.4

Even before the 75-mm. M4 was standardized, Ordnance engineers began work upon a

light-weight, mechanically-loaded air cannon. An entirely new recoil mechanismin which the cylinder was concentric about the gun tube reduced both silhouetteand weight. By using a new high-strength alloy steel having an elastic limit of130,000 pounds per square inch, the designers lowered the weight of the gun alone to 406 pounds. When metallurgical tests at Watertown Arsenal and firing testsat Erie Proving Ground established the greater strength of hollow quenched oversolid quenched gun tubes and breechblocks, the former method of manufacture wasincluded in the specifications. An automatic fuze setter-rammer saved the spacerequired for manual loading and permitted firing at a rate of 30 rounds per minute. Two models of this light-weight cannon varying from each other only in minor


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details were standardized in 1944 as the 75-mm. AN-M5A1 and the M10.5

Early in 1943 the 37-mm. M9 for strafing mechanized ground troops and the 75-mm.M4 for destroying heavily armored ground targets were serving their purpose well enough to inspire work upon a still more powerful gun. Tests at Eglin Field, Florida, comparing the effectiveness of existing rockets and air cannon pointed to the superiority of the latter. Development of a 105-mm. aircraft gun, therefore, was started in July 1943 with endeavor to adapt a 105-mm. howitzer to use forair-to-ground attack. A year later numerous changes necessitated by the excessive blast of the first models led to making a new approach. The resulting T7 105-mm. aircraft gun was test fired late in 1944 only to show that the feed mechanism required further study. Before the changes were completed the war ended and the project was canceled.6"

#######################################75-mm M6 Tank Cannon

Wikipedia indicates this was the gun used on the M24 Chaffee. It also indicatesit was 40-calibers but the data fact sheet shows the same calibers length as theM3.410-lbs same ballistics as the 75-mm m3.Unsourced data fact sheet. Which hints it may have been used on some search-light tanks.

#######################################75-mm M10 Aerial cannon.406-lbs same ballistics as the 75-mm m3.

The strange case of the flying Grizzly and its 75mm gun (internet article)

"THE M10 CANNON

To arm the A-38 was the new-designed T15E1 (M10) 75-mm cannon. It was designedto enable the A-38 to destroy enemy bunkers, tanks, and positions with just asingle shot, while it also placed random surface ships and submarines on the

menu. The gun, in essence, could assassinate a building or destroy a destroyerif given the opportunity.

The entire front section of the gun forward of the recoil band protruded throughthe nose of the A-38

Air cooled with an 84-inch long barrel, the gun was huge, being 12-feet longfrom end to end when fully assembled. However, it was extensively stripped ofexcess material, making it 'just' 406-pounds in weight, which is pretty lightfor a 75mm cannon. Semi-auto, it could fire a 15-pound, 26-inch long shell every

two seconds. These rounds, fired at 2030 fps, could penetrate nearly four-inchesof steel armor.

Why don't you know about the Grizzly/M10 combo?

Well, the fact was that the plane came too late. First flying in the summer of1944, the weapon worked beautifully in tests, as did the aircraft, however thewar was winding down, and no orders came for Beech..."


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#######################################3-inch Towed AT Gun M5

Wikipedia: "Prior to World War II, the primary US anti-aircraft gun was the 3-inch M1918 gun (76.2 mm L/50), a widely-used caliber for this class of weapon. Similar weapons were in British, Soviet and other arsenals. There had been severalupgrades to the weapon over its history, including the experimental T8 and T9 versions developed in the early 1930s that were intended to enter service later inthe decade.

However the US Army became interested in a much more capable weapon instead, andon June 9, 1938 it issued a development contract calling for two new guns, oneof 90 mm which it felt was the largest possible size that was still capable of being manually loaded at high elevations, and another, using assisted loading, of120 mm caliber. The new design seemed so much better than developments of the older 3-inch that work on the 3-inch T9 was canceled in 1938 just as it became production-ready." [90 mm Gun M1-M2-M3 - Wikipedia, the free Encyclopedia]

Began work around 1940. Original pilot model tube of T9 3-inch AA gun used to create 3-inch Gun T10, Recoil mechanism T5, Carriage T1. Carriage based on M2 Carriage of 105mm howitzer.

September 1941 pilot tested at Aberdeen Proving Grounds and worked so well an order for 100 was authorized.

March 1942 Field Artillery Board (FAB) tested at Fort Brag and found a lot of issues that needed to be addressed. No immediate interest; too heavy for infantryand Tank Destroyers wanted a motorized weapon.

August 1942 head of Army Ground Forces General Lesley McNair (staunch supporterof artillery and the idea that towed anti-tank guns were superior to tanks) started it again with orders for 1,000.

December 1942 production of the 3-inch Gun M5 on Carriage M1 began.

#######################################

76-mm M1 Series Tank Gun

Why a 3" and not 75 for the 76-mm M1?

The 3-inch caliber was chosen (according to a phone call transcript between General G.M. Barnes in charge of Ordnance Research & Development and General Joe Devers Head of Armored Forces because the 75-mm driving band was not fit and wouldhave to be modified for high velocities whereas they had plenty of 3-inch rotating bands "I would have considered using the 75, but we'd have to redesign the projectile because the rotating band wouldn't take that velocity. So we had to goto 3"...":

GEN. BARNES: The new 76 mm. gun. The objective that we're after is to be able togive you, in the same space, a gun of 2600 ft.s. muzzle velocity, same power, exterior ballistics as the 3" high power gun. We use the 3" bore for the gun in order to use the 3" projectile which is under manufacture. We have to assemble anew cartridge case in it in order to get the power, so we call the gun a 76 mm so it won't be confused with the 75 or 3". Now, that gun will penetrate 3" of armor at 3,000 yds. and give you all the fire power we feel you'll probably need. And we can put it in the M4 tank without a single change in the tank except in your ammunition racks. While we're making the guns we can, of course, change the face plate on the tank and push the gun about 6" further out into the atmosphere


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and make a better arrangement inside the turret, because with this long gun we have to add some weight to the gun guard (recoil guard) in order to bring it intobalance for the gun stabilizer. Of course we are all crazy about the thing downhere because it puts you so far ahead of everybody else in fire power, and so what we want to do is to go ahead with the initial order of 1,000 guns, of whichwe will be able to get two or three hundred of in a month and a half and as a starter, while you people are making up your mind how many in the long run you'llwant of these, and how many of the short guns.

GEN DEVERS: How much longer is this than the 75? It isn't as long as the present3" is it?

B: Yes, it's a little longer than the 3". It's 52 calibers long. The old 3", I mean the old 75, is 35 calibers or 32, I've forgotten which.

D: Well,. what is the 3" A.A.? How many calibers long?

B: That's about 50.

D: In other words, this is 2" longer than that.

B: 2 calibers - 6" longer.

D: I think that's fine. The only thing that worries me a little bit now is that

this isn't going to throw us off on our present set-up so we can get to fighting. I'm anxious to get M-4 tanks with anything in them so we can go to fighting.

B: It won't have any effect on that at all. We'll keep it off to one side. We won't allow it to interfere in any way either with this program or with the 3" guns on the self-propelled mounts. What it'll do is to put you out several years ahead of anybody else on fire power

D: That's what we're after and it's along the proper lines. It won't complicatethe ammunition supply now, will it?

B: Well, to this extent: You're going to have to have a round of ammunition called a 76 mm. as far as you're concerned. And that's different from the 75 or the

3".

D: What does this projectile weigh?

B: It's the 3" projectile.

D: The only difference is the cartridge case?

B: That's right

D: The 75 weighs 14.4. What does that 3" weigh?

B: About 15 lbs

D: There's not much difference, is there?

B: No. I would have considered using the 75, but we'd have to redesign the projectile because the rotating band wouldn't take that velocity. So we had to go to3" in order to give you that velocity, and of course we have a nice stock of 3"on hand and are making them all the time.

D: Well, how many rounds are we going to be able to carry in a tank? Will it complicate that?


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B: Well, it will reduce the number that you can carry, I don't know how much, because we haven't had time to study that out yet. Now, I thought either you, or you'd want to send someone up to Aberdeen to see the job. In order to save time we want to go ahead, with your permission, on 1,000 because of course we can stopthat at any time. But time is of the essence here, as you know as well as I do,so I think we ought to start it and then work out the details later.

D: Well, all right then. This won't slow up anything we're doing?

B: That's right.

D: It's advance. It's looking six to eight months ahead.

B: That's right.

D: Well, I see no reason you shouldn't do it. I'll send someone up to Aberdeen right away.

B: All right, thanks very much

[The Chieftain's Hatch General Barnes makes a 'Phone Call The Chieftain's Hatch World of Tanks]

------In SHERMAN: ARMORED THUNDERBOLT Zaloga indicates that the 3-inch gun was "...derived from World War I antiaircraft and coastal defense guns."

"Though advances in metallurgy by 1942 had enabled the Ordnance Department to build light but powerful 76-mm. and 90-mm. guns out of newly developed, thin, higher physical steel, Ordnance men were convinced that medium tanks, whether mounting 76-mm. guns or 105-mm. howitzers, must be supplemented by heavy tanks." [Ordnance Department; Planning Munitions for War CMH_Pub_10-9, pg. 237]

Working on their own without a requirement presented by others, Ordnance began developing a 3-inch/76-mm class weapon early in 1942. The 3-inch M7 designed for

the M6 heavy tank and M10 tank destroyer were too heavy and big. Needed smallerweapon so they started the T1 project to fulfill it. Different cartridge than the 3-inch, same projectiles, designated it the 76-mm to reduce confusion. (M4 76mm Sherman Medium Tank Osprey NV 073 pg 4)

1 08/20/422 08/21/423 08/22/424 08/23/425 08/24/426 08/25/427 08/26/428 08/27/42

9 08/28/4210 08/29/4211 08/30/4212 08/31/4213 09/01/4214 09/02/4215 09/03/4216 09/04/4217 09/05/4218 09/06/42


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19 09/07/4220 09/08/4221 09/09/4222 09/10/42

Development of the 76-mm M1 and M1A1 started July 1942. (British and American Tanks of World War II, 117).

Project began August 20, 1942 and finished gun supplied by September 10, 1942. [22 days] 80 more produced in "Autumn 1944". Weighed 300 pounds more than the 75-mm; AP ammo 600 fps faster; HE ammo 1,300 fps faster [seems to be "standard" andnot "super-charged"). [Ordnance Department; Planning Munitions for War CMH Pub10-9 pg 326, 327]

Summer 1942 first 2 guns built and sent to Aberdeen Proving Grounds one for proofing from a fixed stand and the second to be mounted on the standard M34 mount of an M4A1 tank. The 57-calibers length barrel caused traverse issues due to excess forward weight so length reduced from L/57 to L/52, and installed a counterweight on the breech. In SHERMAN: ARMORED THUNDERBOLT Zaloga indicates the prime concern was the issue of shipping and the threat of the weapon digging into the earth is travelling downhill.

[Which is odd how Army pamphlets and those who quote them indicate the 76-mm use

d the 3-inch barrel.] (M4 76mm Sherman Medium Tank Osprey NV 073 pg 4)

It did not match the ballistics and power of the 17-pounder British nor 75-mm L/70 of the Germans but was closer to the German Pak-40/KwK and KwK.

All four: (M4 76mm Sherman Medium Tank Osprey NV 073 pg 4 or 5 for 1st 3) lb. PSI chamberWeapon propellant MV fs. pressure-----------------------------------------------75-mm M3 2 2030 38,00076-mm M1 3.75 2600 43,000 [Zaloga 38,000]3-inch M7 4.87 2600 38,000

4.87 x 1.33 = 6.48: 76-mm propellant 8.42 lb.

German 40 75mm L43 -- 2450 --German 40 75mm L48 -- 2600 --British 17pdr. 9 2950 47,000 [Zaloga 48,000]German 75mm L/70 8.1 3070 48,0008.8-cm KwK 36 2700 33,00090-mm M3 7 2800 38,000105-mm How. M4 3 1550 28,000

August 1942 Ordnance Committee suggested standardizing the original L/57 T-1 asthe M1 76mm gun while the L/52 version became the M1A1.August 1942 Ordnance recommended manufacture in 1943 of 1,000 76-mm armed M4A1s.November 1942 Devers rejected "...this untried weapon." SHERMAN: ARMORED THUNDER

BOLTGeneral Jacob Devers (Head of Armored Force) would not accept as they had yet totest it. (M4 76mm Sherman Medium Tank Osprey NV 073 pg 5)

The suggested order of 1,000 tanks was cancelled December 1942.

Fact finding mission to Tunisia revealed the belief the 75-mm M4 was the best tank then in use; in Britain they concurred but also realized heavier German armorwas going to be met in the future and hence the 17-pounder was being developed.Devers changed his mind and authorized further development of the M4 tank and 7


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6-mm M1 gun to determine how many 76 armed tanks to field. "The new high power 76mm gun should be immediately tested in the M4 tank to determine what percentageof these guns should be installed in future tanks. ... The further perfection of the M4 tank, the best on any front today, should be aggressively continued."

At the same time the decision was made to begin using telescopic sights rather than periscopic and the M34A1 mount/sight combo developed. The 76-mm M1 was mounted on it.

Standard turret of 75-mm armed Sherman too small. (British and American Tanks ofWorld War II, 117).

Turret was not balanced by internal counterweight; did not try to attach external counter-weight ad-hoc but rather than Pressed Steel Car Company produce a newcast turret that had the counterweight on back: 12 M4A1 (76M1). Feb. 1943 shipped one to the Armored Board at Fort Knox and they decided that there was too little inside space and did not accept the entire "quick fix" approach. Only 3 keptas-is, the other 9 being remodled to 75-mm tanks.

Devers had argued with general Lesley McNair too much so he got him out of the way by promoting him in May 1943, sending him to become interim commander of theEuropean Theater of Operations. General Alvan Gillem took his place. [M4 76mm Sherman Medium Tank Osprey NV 073 pg 6-7 confuses this by putting the details hither wither.]

SHERMAN: ARMORED THUNDERBOLT: McNair then reduced the impact of the Armored Force by renaming it Armored Command and in Feb. 1944 to the Armored Training Center, leaving Fort Knox's participation in tanks to be advisor through the Fort KnoxArmored Board testing section. He did this to take over tank requirements.

Ordnance switched to the T23 medium tank turret design starting with pilot models authorized June 17 1943 and delivered July 1943 as M4E6. August 17 1943 testsresulted in recommendation for production by Armored Command HQ: 1,000 be produced with the note "As soon as the tank has been proven on the battlefield, it isrecommended that we go to one hundred percent replacement of the M4 with 76mm gun." (M4 76mm Sherman Medium Tank Osprey NV 073 pg 6)

Note that Gillem was not the author of this: he was off visiting North Africa and Sicily to get a solid dea of what the Army needed for tanks. When he returnedto find his subordinates had suggested the above, he penned his his poison memo:

"The 76mm Gun M1 as a tank weapon has only one superior characteristic to the 75mm Tank Gun M3/ superior characteristic is armor penetrating power. The 76mm gunwill penetrate on average one inch more armor than the 75mm tank gun M3 at thesame range. The high explosive pitching power of the 76mm gun is inferior to that of the 75mm gun. The 76mm HE shell weighs 12.37lbs and has a charge of .86lbsexplosive. The 75mm shell weighs 14.6lbs and has a charge of 1.47lbs of explosive. The exterior ballistics generally of the 76mm gun are less satisfactory for ageneral purpose medium tank weapon than the 75mm gun. The 76mm gun has an extremely heavy muzzle blast, such that the rate of fire when the ground is dry is co

ntrolled by the muzzle blast dust cloud. Under many conditions this dust cloud does not clear for some eight to thirty seconds. The presence of this heavy muzzle blast makes sensing the round extremely difficult for the tank commander and gunner."

Interjected facts in (M4 76mm Sherman Medium Tank Osprey NV 073 pg 7) to illustrate the importance of HE ammo: Typical number of rounds fired by US tanks duringthe war were: 70% HE, 20% AP, 10% smoke. Poor HE shell was damning. [And yet the M10s had not complained, but rather were commended for their weapons effect!]


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Gillem did not intend to stop acceptance but rather pursue a moderate acceptanceof 1 76-mm tank per 3 75-mm armed tanks; 1 platoon per company; or one companyper battalion. Agreed with switching production to 50% (since many 75s had beenproduced already) but not 100%. (M4 76mm Sherman Medium Tank Osprey NV 073 pg 8)

His recommendation swayed McNair to accept the 76-mm for production. Was to be introduced with the 2nd Generation Sherman with multiple updates.

February 1944 tanks using the larger T20/T23 turrets standardized and entered production lines. (British and American Tanks of World War II, 117).

Late 1943 first production and January first receipts.

In production improvements of the 76-mm M1: allowing gun to be moved forward toimprove balance; muzzle brake to tame blast (production began July 1944). Guns threaded for (or mounted with) designated M1A1C. Thread protector fit on many that were fielded before receiving the brake.

M1A2 same as M1A1C but with new rifling twist of 1:34 rather than 1:40.

Heavier gun and heavier turret led to exploration of traction and flotations solutions and eventual adoption of HVSS starting March 1944 and full scale April 1944.

17-pdr Option for M4 Tanks--------------------------August 1943 British offered to convert some US tanks to 17 pounder. Ordnance dissuaded by tests they had witnessed - excessive muzzle blast and some flash-backat the breech.

March 25, 1944. Aberdeen Proving Ground in the US tested the 90-mm vs. 17-pdr.May 23, 1944. Tests in Britain.British offer of 200 guns and ammunition per month within 3 months of any acceptance of their offer.1. U.S. already producing both the 90-mm and 76-mm and ammunition; 17-pdr. woul

d not appear until after Normandy.2. Developing HVAP T4 shot for the 76mm. [Not later?](M4 76mm Sherman Medium Tank Osprey NV 073 pg 9)

---------------------------90-mm M3, and AA Gun"Realizing that still heavier guns would be required to insure American superiority on the battlefield, General Barnes in September 1942 ordered the initiationof a project adapting the high-powered 90-mm. antiaircraft gun to use in combatvehicles. Design of the 90-mm. tank gun T7 was completed in December of the sameyear, but neither the 76-mm. nor the 90-mm. weapons were destined to see actionuntil the autumn of 1944.8"[Ordnance Department; Planning Munitions for War CMH_Pub_10-9, pg. 328]

"Though advances in metallurgy by 1942 had enabled the Ordnance Department to build light but powerful 76-mm. and 90-mm. guns out of newly developed, thin, higher physical steel, Ordnance men were convinced that medium tanks, whether mounting 76-mm. guns or 105-mm. howitzers, must be supplemented by heavy tanks." [[Ordnance Department; Planning Munitions for War CMH_Pub_10-9, pg. 237]

"Prior to World War II, the primary US anti-aircraft gun was the 3-inch M1918 gun (76.2 mm L/50), a widely-used caliber for this class of weapon. Similar weapons were in British, Soviet and other arsenals. There had been several upgrades to


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the weapon over its history, including the experimental T8 and T9 versions developed in the early 1930s that were intended to enter service later in the decade.

An M26 Pershing armed with the 90 mm gun

However the US Army became interested in a much more capable weapon instead, andon June 9, 1938 it issued a development contract calling for two new guns, oneof 90 mm which it felt was the largest possible size that was still capable of being manually loaded at high elevations, and another, using assisted loading, of120 mm caliber. The new design seemed so much better than developments of the older 3-inch that work on the 3-inch T9 was canceled in 1938 just as it became production-ready. By 1940 the second development of the 90 mm design, the T2, wasstandardized as the 90 mm M1, while its larger cousin became the 120 mm M1 gun.

A few hundred M1s were completed when several improvements were added to producethe 90 mm M1A1, which entered production in late 1940 and was accepted as the standard on May 22, 1941. The M1A1 included an improved mount and spring-rammer on the breech, with the result that firing rates went up to 20 rounds per minute.Several thousand were available when the US entered the war, and the M1A1 was their standard anti-aircraft gun for the rest of the conflict. Production rates continued to improve, topping out in the low thousands per month.

Like the German 88, and the British QF 3.7 inch AA gun, the M1A1 found itself facing tanks in combat, but unlike the others it could not be depressed to fire against them. On September 11, 1942 the Army issued specifications for a new mountto allow it to be used in this role, which resulted in the 90 mm M2, introducing yet another new mount that could be depressed to 10 degrees below the horizontal and featured a new electrically-assisted rammer. It became the standard weapon from May 13, 1943.

Anti-tank developmentsThe M3 was also adapted as the main gun for arious armored vehicles, starting with the experimental T7 which was accepted as the 90 mm M3. The test firing of the M3 took place on an M10 tank destroyer in early 1943. The gun was used on theM36 tank destroyer, and the M26 Pershing tank.

A number of experimental versions were developed on the basic M3 pattern, including the T14 which included a standard muzzle brake, the T15 series with an improved muzzle velocity of about 975 m (3,199 ft) per second, the even higher velocity T18 and the T19, which was an attempt to reduce barrel wear. The T21, which was intended for wheeled vehicles, and the T22, which used the breech from the standard 105 mm M2 howitzer to take larger charge cartridges. None of these versions entered service.

In the post-war era development of the T15 continued as the T54, which includedthe ability to fire tungsten-cored shells at much higher velocities. The T54 wasthe main armament of the M47 and M48 Patton tanks, and the M56 Scorpion anti-tank vehicle.

" [90 mm Gun M1-M2-M3 - Wikipedia, the free encyclopedia]

90-mm T8 AT Gun--------------------------------------------"The M1 90mm gun was mated with the M2 recoil mechanism from the 105mm howitzeras the 90mm gun T8, and mounted on a new carriage designated as the T5." [ZalogaU.S. Anti-Tank Guns]


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"90mm gun T13 and Gun Carriage T9...the entire assembly weighed only 6,8501b, compared to 9,9501b for the T8 90mm gun with T5E2 carriage.

Two further lightweight 90mm gun designs were initiated in July 1944 using moreconventional carriages: the T20 90mm gun with T14"

90-mm T15 SuperVelocity--------------------------------------------

"7. 90mm TANK GUN - SUPER VELOCITY: 17 March 1944, the design of the super-velocity 90mm Gun, T15, was undertaken. This gun was designed to use a standard 90mm projectile in a new case. The new cage has the same exterior diameter asthe discarded case, but the length has been increased to provide a greater powder capacity.

This gun was designed to give a velocity of 3,200 f/s with single-base powder. The design was also such that it could be used interchangeably with the standard 90mm tank gun, M3, except of course, for ballistics. The gun is very Long (70 calibers) and would require the use of a new equilibrator and stronger parts in the mount. However, this gun can be mounted in the T26E1 Tank.

The pilot gun was delivered to Aberdeen on 1 September 1944 and is now being used to develop powder. If the war continues, several hundred of these gunswill be manufactured for mounting in the T26E1 Tanks in order to provide a gunof greater firepower."[US Gun Development Memo 1944 10 11]CALCULATED LOAD:

Shot Weight is assumed:2900 lb. 24.5 lb. AP @ 3200 f/s = 143-mm/5.6-in. @30; 159-mm/0-in. @0

--------------------------------------------105-mm Howitzer M4 in Sherman M4

November 1942 initial physical work with began. [Sherman: History... 208]Standard M2A1 was a poor fit as loader had to insert round from one side and reach across to activate breech closure.Balance was atrocious: power traverse failed at 30 pct. or higher slope.Created the lighter T8 howitzer which became the M4.Revised shorter breech block, new operating handle easily used.Took out gyrostabilizer and power traverse.

Improved ammo storage and telescopic sight.Improved elevation range -10 to +35 degrees.Combination mount M52.Same basic turret as 75-mm model tank.68 rds. 105-mm (2 in ready racks, 21 in 2 racks in right sponson, 45 in floor racks). [Typical quote is 66 rounds; perhaps the 2 ready rack were removed?]Hunnicut regarding M67 HEAT: ...the highly curved trajectory of the low velocityhowitzer...made it hard to hit ...except at very close range.

[Weapons of the Tankers, 93-94]Limted velocity resulted in typical maximum range of 1,000 yards direct fire.6 x 105-mm Armed M4s per tank battalion as a single armored artillery battery.M10 assault trailer: 54 rounds

After war interviews revealed dislike of the non-powered turret which preventeddiscouraged direct fire.HE rounds could demolish smaller vehicles and AT guns with sheer blast.[Weapons of the Tankers, 93]

Production Febuary 1943 to end of war.

--------------------------------------------105-mm T4"By September 1943, the very powerful 105mm Gun, T4, had been designed and a pil


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ot manufactured for antiaircraft use. Since this gun can fire a 42-lb. armor-piercing projectile at 2,800 f/s, 5.5 inches of armor at 30 inclination can be penetrated at a range of 2,000 yards." [US Gun Development Memo 1944 10 11]

CALCULATED LOAD:3800 lb. 42 lb. AP @ 2800 f/s = 157-mm/6.2-in. @30; 175-mm/0-in. @0

--------------------------------------------105-mm T88 tons/16,000 lb.39 lbs. @ 3,100 f/sQAP: 210-mm/8.26" @ 1,000 y @ 0-dgrees.CALCULATED LOAD:4300 lb. 39 lb. AP @ 3100 f/s = 162-mm/6.4-in. @30; 180-mm/0-in. @0

Wikipedia quoting Zaloga U.S. Anti-Tank Guns.

Anti-tank Guns Usa Early Ww II (True Fact)

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