Despite the M3's effectiveness, the tank's unconventional layout and the limitations of its hull-mounted gun prompted the need for a more efficient and versatile design, leading to the development of the M4 Sherman.

Additionally, the M4 featured a one-axis gyrostabilizer, which, while not precise enough to allow for accurate firing while in motion, helped keep the gun roughly aimed in the direction of the target when the tank came to a stop.

Additionally, the tank's size and weight were kept within moderate limits, which facilitated easier shipping and compatibility with existing logistical and engineering equipment, including bridges and transport vehicles.

The M4 Sherman was designed to be more versatile and easier to produce than previous models, which proved vital as the United States entered World War II.

The ability to produce the Sherman in large numbers, combined with its operational flexibility and effectiveness, made it a key component of the Allied war effort.

[10][b] Tank destroyer battalions using vehicles built on the M4 hull and chassis, but with open-topped turrets and more potent high-velocity guns, also entered widespread use in the Allied armies.

[3] The Sherman's reliability resulted from many features developed for U.S. light tanks during the 1930s, including vertical volute spring suspension, rubber-bushed tracks, and a rear-mounted radial engine with drive sprockets in front.

[citation needed] As the United States approached entry into World War II, armored employment was doctrinally governed by Field Manual 100–5, Operations (published May 1941, the month following selection of the M4 tank's final design).

By the time M4s reached combat in significant numbers, battlefield demands for infantry support and tank-versus-tank action far outnumbered the occasional opportunities of rear-echelon exploitation.

Although the American industrial complex was not affected by enemy aerial bombing or submarine warfare as was Japan, Germany and, to a lesser degree, Great Britain, an enormous amount of steel for tank production was diverted to the construction of warships and other naval vessels.

According to Soviet tanker Dmitriy Loza, the Sherman was held in good regard and viewed positively by many Soviet tank crews, with compliments given to its reliability, ease of maintenance, generally good firepower (referring especially to the 76 mm gun version)[44] as well as an auxiliary power unit (APU) to keep the tank's batteries charged without having to run the main engine, as was required on the T-34.

[57] The M4A3E8 and T-34-85 were comparable and could destroy each other at normal combat ranges, although the use of High-Velocity Armor Piercing ammunition, advanced optics, and better crew training gave the Sherman an advantage.

The Army also failed to anticipate that the Germans would attempt to make the Panther the standard tank of their panzer divisions in 1944, supported by small numbers of Tiger I and IIs.

An attempt to upgrade the M4 Sherman by installing the 90 mm-armed turret from the T26 tank project on an M4 hull in April 1944 (referred to as the M4/T26) was halted after realizing it could not go into production sooner than the T26 and would likely delay T26 development.

[71] In testing before the invasion of Normandy, the 76 mm gun was found to have an undesirably large muzzle blast that kicked up dust from the ground and obscured vision for further firing.

The addition of a muzzle brake on the new M1A2 gun (which also incorporated a faster rifling twist leading to a slight accuracy increase at longer ranges) beginning in October 1944 finally solved this problem by directing the blast sideways.

[78] In late summer 1944, after breaking out of the bocage and moving into open country, U.S. tank units that engaged German defensive positions at longer ranges sometimes took 50% casualties before spotting where the fire was coming from.

[85] However, British Army test results conducted with two Fireflys against a Panther turret-sized target demonstrated relatively poor accuracy at long range; a hit probability of 25.4% at 1,500 yd (1,400 m) with APCBC, and only 7.4% with APDS.

By then, the end of the war in Europe was clearly in sight, and the U.S. Army decided the logistical difficulties of adding a new ammunition caliber to the supply system was not warranted.

In fall 1943, Lieutenant General Devers, commander of U.S. forces in the European Theater of Operations (ETO), asked for 250 T26 tanks for use in the invasion of France; McNair refused, citing the fact that he believed the M4 was adequate.

Soon after the Normandy invasion in June 1944, General Dwight D. Eisenhower urgently requested heavy tanks, but McNair's continued opposition to mass production due to persistent serious mechanical problems with the vehicles delayed their procurement.

[98] The 105 mm-armed variants were issued the M67 high-explosive anti-tank (HEAT) round; although very effective the low muzzle velocity made hitting enemy armor difficult.

[112] John Buckley, using a case study of the British 8th and 29th Armoured Brigades, found that of their 166 Shermans knocked out in combat during the Normandy campaign, 94 (56.6 percent) burned out.

Field improvisations included placing sandbags, spare track links, concrete, wire mesh, or even wood for increased protection against shaped-charge rounds.

The higher weight required changing the transmission gear ratios to reduce maximum speed to 22 mph, and crews were warned not to let the suspension "bottom" too violently.

[121] In its initial specifications for a replacement for the M3 medium tank, the U.S. Army restricted Sherman's height, width, and weight so that it could be transported via typical bridges, roads, railroads, and landing craft without special accommodation.

[122] A long-distance service trial conducted in Britain in 1943 compared diesel and gasoline Shermans to Cromwell tanks (Rolls-Royce Meteor engine) and Centaur (Liberty L-12).

Lieutenant Colonel Wilson M. Hawkins of the 2nd Armored Division wrote the following comparing the U.S. M4 Sherman and the German Panther in a report to Allied headquarters: It has been claimed that our tank is the more maneuverable.

Duckbills began to reach front-line tank battalions in fall 1944 but were original factory equipment for the heavy M4A3E2 Jumbo to compensate for the extra weight of armor.

Greater Sherman production and availability meant that the Ram was never used in action as a gun tank, being either used for training or converted to Kangaroo armored personnel carriers.