En efecto, al principio en 1943, los americanos pensaron que el cañón de 76mm era adecuado, ya en el verano de 1944 cuando se mostró deficiente, hubo en un primer momento la urgencia por adoptar el 17 lbs británico, pero después de Normandía la cantidad de blindados alemanes disminuyó en el frente occidental, por lo que se pensó de nuevo que no sería necesario, esta vez por falta de blindados alemanes, esta opinión volvió a cambiar durante la batalla de la Ardenas, y se llegó a destinar un lote de Shermans americanos para equiparlos con el cañón de 17 lbs británico, pero la guerra estaba por acabar cuando este primer lote de tanques estaba listo y al no ser necesario el programa se cancelo.¿Puede que no se le diera más urgencia a la introducción del Firefly por que se pensó que el 76 mm sería suficiente para lidiar con los "gatos" alemanes? De este si que se incrementó de manera constante y sustancial el número de unidades durante toda la contienda en Europa.
El que los americanos pensaran que el 76mm era suficiente para lidiar con Tigers se debió a una combinación de errores técnicos, nacionalismo y creerse su propia propaganda.
Los siguientes fragmentos pertenecen al libro "Tank Tactics From Normandy to Lorraine" de Roman Jarymowycz específicamente del capítulo "Who killed the Tiger The Great Tank Scandal". páginas 257-263. Los resaltados son míos.
"The Allies had defeated Tiger tanks in North Africa in the early months of 1943; there had been nearly twelve months of battle in Italy. Tigers had been living in British captivity for well over a year. Why suddenly did the Allies face a tank scandal? Initial contact with the Tiger suggested that it could be knocked out by the 6-pounder antitank gun: although a trial was ordered to prove these findings, it was never completed.7"
"The result was the alarming state of British tanks: underarmored, undergunned, and mechanically unreliable (with the cooling system installed backwards to suck in hot air from the engine and roast the crew... it took forever to perform the simplest repairs).
The best the British could do is come up with the excellent 17 pounder gun and agree that the only decent tank to mount it on was the American Sherman U.S. armor´s attempts to create a suitable battle tank were blocked by McNair and the bias of american industry and U.S. Army Ordnance against the logical Firefly (Sherman M4) solution.14"
"American faith in the 76mm gun and the tank destroyer would not be shaken until Normandy, when it was too late, and Bradley was reduced to begging Montgomery for Fireflies -of which the British and Canadians armored divisions had none to spare.
The tank scandal should not have come as a total surprise to Allied generals. Still, despite detailed reports from military attachés in Moscow and their own after action reports, SHAEF was unprepared for the Tiger or Panther. There were three reasons for this. First initial successes supported upbeat reports, and pessimistic warnings were brushed aside. Second, aborted field test forced commanders to await detailed ordnance studies from Bovington, England and Aberdeen Proving Ground, Maryland, whose test arrived too late(confident initial predictions by ordnance teams testing the 76mm gun soothed misgivings and prompted the U.S. refusal to adopt the British 17-pounder as an interim solution until it became too late to do anything about it), Third, although Tigers had been captured, Panthers had not been evaluated at all. The first time the Allies met the Pzkw V Panther in actual combat was after the Allied breakout from Anzio. By then the Normandy invasion had begun. The first detailed Panther reports read by Eisenhower´s staff would be from their own troops in Normandy."
"The anticipated debut of a Tiger battalion on the western Front turned out to be a dud rather than a shock. The Afrika Korps Tigers were nailed by 6-pounder antitank guns from defilade positions that engaged the only sections of the Pzkw VI that could be penetrated, the flank and the rear hull. The knocked out monsters were examined with more curiosity than awe. Initial reports were enthusiastic: our antitank guns can kill Tiger.17
This was dangerously misleading. The after action estimates were based on overoptimistic evaluations and incomplete investigations. The only attempted test (3 February 1943) ended in failure. Eventually a British technical staff field officer, Lt Col. Neville, managed to conduct one controlled trial with plates that had been removed from Tiger by oxyacetylene cutting, the results should have set off the alarms throughout the armored corps but fell through the cracks.19
The next series of accurate test would be conducted at Bovington, Larkhill, and Chobham. They would take months, and their results when published, were too technical and too late to create any feverish response at SHAEF. The Allied General Staff liked what it first was told about the Tiger -that it was easy to kill. Besides, the 6 pounder gun was about to be augmented by masses of 76mm and 17 pounder guns, which the generals were promised, would take care of any German tank. Accordingly, General Mc Nair opposed the production of the latest U.S. heavy tank, the T26 (M26 Pershing). The AGF policy statement concluded the following:
"The recommendation of a limited proportion of tanks carrying a 90mm gun is not concurred in for the following reasons: The M4 tank has been hailed widely as the best tank on the battlefield today... There appears to be fear on the part of our forces of the German Mark VI (Tiger) tank. There can be no basis for the T26 tank other than the conception of a tank vs tank duel which is believed to be unsound and unnecessary. Both British and American battle experience has demonstrated that the antitank gun in suitable numbers is the master of the tank... There has been no indication that the 76mm antitank gun is inadequate against German Mark VI tank."
"During the winter of 1943, while formal tests were being conducted at Chobham.22 one of the captured Tiger was put on public display at Horse guards Parade in the center of London23 U.S and Canadian armored officers joined British school kids climbing over the tank and were relieved to find that it was a sitting duck for any 6 pounder gun. The Truth was the exact opposite. Secret trials quickly proved that although the Tiger could be killed by a short range, flank-fire, should it choose a less aggressive tactic and select to fight it out at long range, there was not an allied tank in the inventory that could kill a Tiger. In fact, Royal Ordnance scientists discovered to their horror that the Tiger could not be penetrated at any range. Point blanck engagements at under 100 yds proved that 6 pounder and 75mm tank guns could not defeat the Tiger´s frontal armor. The rounds simply bounced off."
"The 76mm M1A1 stood a slightly better chance, but the up-gunned Shermans were unobtainable; not a single 76mm was available on 6 June 1944. By September only 250, out of the 1,913 tanks in the 12th Army Group, were A4 Shermans."
"The British lobbied to have masses of 17 pounder Shermans built in the United States. The Americans dug in their heels; British advise was suspect. The record spoke for itself. British tanks were inferior: the only reason the British had won in the desert, American tank designers said in private, was because American tanks like the Grant ans Sherman arrived in time. It was American armor not British, that won in Africa.Although exaggerated, the theory was not altogether untrue.26"
"The British could not even convince the Americans to build Fireflies. The 17 pounder was not considered sufficiently superior to the 76mm tank gun to warrant American production. Devers refused to attend a shooting demonstration that compared the 17 pounder with the 76mm and 90mm guns. Rejected in Detroit and Washington, Ross advised Whitehall that if the British wanted Fireflies they would have to build them themselves. The British did that but given the chaotic state of their industry, the best they could manage by 6 June 1944 was a 25% replacement."
7. Report on German Pz Kw VI Tank Examined 23 February. War diary Weapons Technical Staff Field Force. Col. J.A. Barlow and Lt. Col. R. D. Neville North Africa, February 1943.
14.The British director general of artillery, Gen. Campbell Clarke, sent a sample 17-pounder gun to the British inspector general of armament in Canada, and the British Technical Mission in Detroit was able to obtain dimensions and confirmed that the Chrysler Sherman turret would accommodate the gun well enough.
17. While the Special Technical team was trying to examine the Tiger, the British confirmed information that had already been sent worldwide by Reuters. The Daily Telegraph and The Daily Mirror announced triumphantly "6 pounder Beats New Nazi Tank 5 February 1943.
19.Carried out a firing trial against it with a 6 pdr Mk II. The plate was 102mm thick (the Brinell figure has since been ascertained to be 302), set up at approximately 21 degrees, and supported by drums filled with stones both at the back and at the front. The gun was set up 300 yds away. Two hits were obtained with the following results.
Round...Range......angle.............Result
1.......300 yds....21 degrees........Shot penetrated 3 inches, plate cracked vertically. Shot turned and . rebounded whole.
2.......300 yds....20 degrees........Shot penetrated 3.5 inches. Bulge at back. Plate split in two.
The trial was then suspended. Owing to weather conditions and approaching darkness, photography was not possible. RG 24 BRAC Department of Tank Design Armor Branch "Side Armor of Pz Kw VI Comments on firing trials carried out in N. africa" H. Harris-Jones. Ballistics Section 5 June 1943.
22. U.S. Aberdeen trials of the Tiger were under way by January 1944, with press releases "tamed Tiger" Yank, 21 January 1944. Col. G.B. Jarrett Papers, chief of Foreign Material Branch and Ordnance Research Center, Aberdeen Proving Grounds. MHI.
23.Tigers were stabled at the British School of Tank Technology at Chertsey in October. a Tiger was then placed in Horse Guards Parade for general public inspection in November 1943, The London Illustrated News, 4 December 1943 shows army officers and children climbing over the tank. It was then returned to Chertsey and Lulworth Camp in Dorset for gunnery trials.
26.Brig. Gen. J.H. Coller, commander CC A White, Exhibit No.1
Ahora 2 fragmentos de Armored Thunderbolt de Steven Zaloga
"Of the three methods of increasing antitank performance mentioned earlier, the 3 inch gun used only one, an increased barrel length of L/57, which exceeded the L/32 of the Sherman´s existing 75mm gun. The propellant charge was only 3.6 pounds, less than half that of either the German Panther´s 75mm gun or the British 17 pounder. Whitout permission form AGF or pressure from the Armored Force or Tank Destroyer Center, it proved difficult for Ordnance to justify the development of a whole new antitank gun as was underway in Britain, Germany, and the Soviet Union.
Ordnance tried to develop a better gun on the cheap and US tankers would pay for this shortsightedness on the battlefield in 1944-1945.
The existing M7 3 inch tank gun was already in use on theM10 tank destroyer and M6 heavy tank.However, it had a big and clumsy breech and recoil system. Ordnance redesigned the weapon in a more compact fashion specifically for use in smaller tanks and tank destroyers, calling it the 76mm M1 tank gun. The designation 76mm was used for the gun instead of 3 inch since it required a different propellant casing and hence different ammunition than the other 3 inch gun, even though the 3 inch M7 gun and 76mm M1 gun both shared the same projectiles.
Builders mounted a test example of the new gun in a M4A1 tank and put it through firing trials in the summer of 1942. The gun proved to be well designed, even it a bit much for the Sherman turret. Engineer branch representatives at Aberdeen Proving Ground complained that it violated doctrine since the barrel projected so far in front of the tank that it would be difficult to transport and could get jammed into the ground when the tank descended a hill. As a result, with no special study of the consequences, Ordnance lopped fifteen inches off the front of the barrel, decreasing its length to L/52 and degrading its antitank performance for no especially good reason.
This casual change to the gun is a vivid reminder of the low priority afforded to this program by using branches. The shorter gun was designated as the M1A1 76mm gun and would eventually become the standard production type in 1942."
Páginas 106-108
"From a technical standpoint, Mc Nair´s viewpoint was dangerous; the new 76mm gun was not as powerful as many army leaders thought. The M1A1 76mm tank gun firing M62 APC (armor piercing capped) projectile had a nominal penetration of 109mm at 500 yds with the armor angled at 20 degrees. The Tiger´s gun mantlet was 120mm thick and the hull front 100mm. In practice, the 76mm gun could penentrate the Tiger mantlet only at ranges of 100 meters or less and the hull at 400 meters, while the Tiger could penetrate the M4 Sherman at ranges more than double these figures."
Página 124.
