156 76 mm-armed M4A1 Shermans were sent to England for familiarization in April and May 1944, but were not wanted by armored unit commanders for the upcoming D-Day invasion due to the perceived inferiority of their high explosive shell (0.86 pounds of filler for the M42 shell, versus 1.47 pounds for the 75 mm M48 shell; this inferiority only turned out to be theoretical, as the two shells produced the same amount of fragments). The Panther had been seen at Anzio in February 1944, but U.S. tankers had not encountered them in large numbers, and were confident in the ability of their 75 mm guns to deal with them. The German Panzer Lehr division (officially the 130. Panzerdivision, but almost always known as Panzer Lehr even in official correspondence) counterattacked the positions of the 9th and 30th Infantry Divisions along the Vire River at Le Desert on July 11, 1944 using, among other forces, a battalion of Panthers. The attack was a complete failure and became just a footnote in the Normandy campaign. 30 German tanks were destroyed, damaged, or abandoned at the hands of air attacks by the Ninth Air Force, M4 Sherman tanks and M10 tank destroyers of the 3rd Armored Division and 899th Tank Destroyer Battalion, infantry bazookas, and 57 mm antitank guns. It was soon found that the 3-inch gun M7 of the M10, which was ballistically identical to the later 76 mm gun M1 on the improved Sherman, was wholly unable to penetrate the thick and well-sloped (80 mm at 55 degrees from the vertical, giving an effective thickness of 140 mm) upper glacis armor of the Panther. However, penetrations were achieved at close range (less than 200 yards) through the thinner lower front belly (50 mm at 55 degrees, giving an effective thickness of 87 mm) and turret front armor (100 mm at 10 degrees, giving an effective thickness of 102 mm). The Americans, previously considering the Panther to be a limited-production heavy tank that was easy to knock out based on Soviet intelligence reports, and having failed to examine other data, experienced a rude shock and were sent scrambling for something better.

For the upcoming Operation Cobra, scheduled for late July 1944, 120 of the M4A1(76)Ws sitting idle in England were distributed to the 2nd and 3rd Armored Divisions, which were intended to exploit the planned breakthrough. Fifty were given to each division, with twenty as spares to replace losses. The 3rd Armored Division decided to allocate two to 25 selected medium tank platoons, while the 2nd Armored Division rearmed entire companies to the point where the number of tanks given was exhausted. To streamline logistics for a time after the invasion, all of the tanks initially deployed by the U.S. in Normandy in armored divisions and separate tank battalions were M4 and M4A1 models with the Continental R-975 radial engine.

The first 75 mm and 76 mm-armed M4A3s began to be issued in August 1944. The Ford GAA V-8 engine on these vehicles was ruled a superior tank engine by the Army in 1943; it was light, low-profile, powerful, and provided more torque than the R-975. Various sub-variants of the M4A3 remained the preferred replacement tank whenever possible throughout the rest of the war, although radial-engined models were still issued if necessary. The priority for issue of 76 mm-armed tanks until the end of 1944 was to the armored divisions; separate tank battalions, intended for attachment to divisions, did not move ahead on the priority list until early 1945, and some didn't receive their first 76 mm tanks until then. An oddity was the 774th Tank Battalion, that arrived in Europe in October 1944 completely equipped with 76 mm-armed medium tanks.

A small amount of T4 high-velocity armor piercing (HVAP) ammunition with a muzzle velocity of 3,400 feet per second and greatly increased armor penetration was issued to tank and tank destroyer units beginning on September 11, 1944. The supply of this ammunition was painfully limited for the rest of the war due to unstable reserves of tungsten, and it was often only issued for specific circumstances and unavailable for long periods of time.

The horizontal volute spring suspension, which offered a smoother ride, better flotation over soft terrain, and a greater weight-bearing capacity than the vertical volute spring suspension, entered production on the M4A3(76)W line at Chrysler in August 1944 at serial number 59747 (USA 3031610). The M4(105) and M4A3(105) followed suit in September 1944 at serial numbers 58307 (USA 30111868) and 57842 (USA 30111383), respectively. The other two manufacturers still producing Shermans in late 1944, the Fisher Body division of General Motors (M4A2(76)W and M4A3(75)W) and the Pressed Steel Car Company (M4A1(76)W), were ordered to switch their lines to HVSS no later than January 1, 1945. As the average shipping time for a new tank from the United States to Europe was three to five months, the entire 1945 U.S. production of armored fighting vehicles was basically rendered extraneous to the European war effort. The M4A2 was not used by U.S. forces except the Marine Corps (and the Army for training or extraordinary circumstances); a shipment of 169 M4A1(76)W HVSS had arrived in Europe by April 1945 and had been allocated, but was not divided up further and issued to units.

The first tanks equipped with HVSS built in August and September 1944 did not arrive in Europe until the early winter. The first issue of M4A3(76)W HVSS went to the famed 37th Tank Battalion of the 4th Armored Division on December 22, 1944, who received one platoon's worth. The M4A3(76)W HVSS slowly trickled into Europe throughout the spring of 1945. By the end of the war, roughly half of U.S. medium gun tanks in Europe had the 76 mm gun; roughly half of these had the horizontal volute spring suspension. The M4A3(76)W HVSS was also shipped to Italy, but since the demand for replacement vehicles there was lower than on mainland Europe (i.e. France and Germany), the ones received at ports, like the M4A1(76)W HVSS shipment mentioned above, were allocated but not issued to units before the war ended.

U.S. 12th Army Group M4 Strength, 1944-45:

Tanks|6/44|7/44|8/44|9/44|10/44|11/44|12/44|1/45|2/45|3/45|4/45 :--|:--|:--|:--|:--|:--|:--|:--|:--|:--|:--|:--|:-- 75 mm tanks|646|781|1,317|1,367|1,267|1,521|1,377|1,695|1,749|1,937|1,664|1,449 76 mm (arm'd div.)|||95|117|202|406|418|350|542|624|726|987 76 mm (tank bn)||||95|37|166|177|259|216|305|438|607 76 mm subtotal|||95|212|239|572|595|609|758|929|1,164|1,594 Total M4|646|781|1,412|1,579|1,506|2,093|1,972|2,304|2,507|2,866|2,828|3,043 % 76 mm|||6.7|13.4|15.8|27.3|30.1|26.4|30.2|32.4|41.1|52.3

U.S. 6th Army Group M4 Strength, 1945:

Tanks	1/45	2/45	3/45	4/45	5/45
75 mm tanks	422	381	332	434	523
76 mm tanks	185	208	366	478	557
Total M4	607	589	698	912	1,080
% 76 mm	30.4	35.3	52.4	52.4	51.5

Delivery of M4A3(76)W HVSS to Armies of 12th Army Group in ETO, 1944-45:

Army	12/44	1/45	2/45	3/45	4/45	5/45
First		29	19	57	153	258
Third	21	28	62	13	132	256
Ninth		33	72	45	64	214
Fifteenth		24				24
Total	21	114	153	115	349	752

The only Tiger I tanks in Normandy were in the British and Canadian sector, part of the 101. and 102. Schwere Schutzstaffel Panzerabteilungen and the 503. Schwere Heeres Panzerabteilung. The Panzer Lehr division had a few Tiger I on their rolls during the summer of 1944, but it is unknown if they were used in combat. After Normandy, the vast majority of Tiger I in the West were replaced with the Tiger II, and only two Tiger I units with scarcely more than four dozen tanks in all continued to face Western Allied forces on a regular basis, Schwere Panzerkompanie Hummel (later made the 4th kompanie of Schwere Heeres Panzerabteilung 506), and Panzerabteilung (Funklenk) 301. An ad-hoc unit known as Gruppe Fehrmann took six Tiger I and five Panther tanks from a training school and opposed U.S. and British forces in northwestern Germany after their crossing of the Rhine river in April 1945.

Sources:

• Stansell, Patrick, Kurt Laughlin. The Sherman, Design and Development: A Complete and Illustrated Description of the U.S. M4 Sherman Tank Series in the Second World War. Delray Beach: The Ampersand Group, Inc, 2013.

• Zaloga, Steven J. M4(76mm) Sherman Medium Tank 1943-65. Oxford: Osprey Publishing, 2003.