[4] Later an improved version of the tank entered service as the M5 in 1942 to be supplied to British and other allied Commonwealth forces under lend-lease prior to the entry of the United States into the war.

The upgraded design, with thicker armor, modified suspension and new gun recoil system was called "light tank M3".

Total M5 and M5A1 tank production was 8,884; an additional 1,778 M8 75 mm howitzer motor carriages based on the M5 chassis with an open-top turret were produced.

[17] In this role, they were expected to remain behind the main reconnaissance force as the support element and augment the firepower whenever enemy contact was made.

[18] [It] is apparent that a Light Tank Battalion, armed with only 37mm guns, unless very skillfully employed with Infantry, will suffer severe casualties in men and material.

[20] From mid-November 1941 to the end of the year, about 170 Stuarts (in a total force of over 700 tanks) took part in Operation Crusader during the North Africa Campaign, with poor results.

The Stuart also had a limited range, which was a severe problem in the highly mobile desert warfare as units often outpaced their supplies and were stranded when they ran out of fuel.

[citation needed] The other major Lend-Lease recipient of the M3, the Soviet Union, was less happy with the tank, considering it under-gunned, under-armored, likely to catch fire, and too sensitive to fuel quality.

In the letter sent to Franklin Roosevelt (18 July 1942), Stalin wrote: "I consider it my duty to warn you that, according to our experts at the front, U.S. tanks catch fire very easily when hit from behind or from the side by anti-tank rifle bullets.

Since many hidden fortifications and positions would have survived the initial medium tank assault, the infantry would then be confronted by any remaining fortified German troops.

Lt. Morin, with his 37mm cannon locked in recoil maneuvered his M3 off the road, but took a direct hit while doing so, and his tank began to burn.

By the same measure, although the US was not hampered by industrial restrictions, the U.S. M3 light tank proved to be an effective armored vehicle for fighting in jungle environments.

[38] When the U.S. Army joined the North African Campaign in late 1942, Stuart units still formed a large part of its armor strength.

[citation needed] [check quotation syntax] Though the Stuart was to be completely replaced by the newer M24 Chaffee, the number of M3s/M5s produced was so great (over 25,000 including the 75mm HMC M8) that the tank remained in service until the end of the war, and well after.

In addition to the U.S, UK and Soviet Union, who were the primary users, it was also used by France (M3A3 and M5A1), China (M3A3s and, immediately post-war, M5A1s) and Josip Broz Tito's Partisans in Yugoslavia (M3A3s and few M3A1).

With the limitations of both the main gun (see below) and armor, the Stuart's intended combat role in Western Europe was changed significantly.

[c] On 9 December 1944, the 759th Tank Battalion advanced on a hill near Bogheim but was subjected to a counter-attack by German forces, including a heavy self-propelled assault gun, which took "over 100 direct hits" at ranges as low as 75 yd (69 m) with "no appreciable damage".

The M5 played a significant role in the First Kashmir War (1947) between India and Pakistan, including the battle of Zoji-la pass fought at an elevation of nearly 12,000 ft (3,700 m).

M3A1 and M3A3s were used by British forces in Indonesia during the Indonesian National Revolution, where they suffered heavy losses due to the Stuart's thin armor plating.

[46] During the 1960s and 1970s, the Portuguese Army also used a small number of M5A1 light tanks, out of a total of 90 received as military aid from Canada in 1956, in the war in Angola, where its all-terrain capability (compared to wheeled vehicles) was greatly appreciated.

The vehicles were mostly employed for convoy escort and recovery duties and limited counterinsurgency operations against National Liberation Front of Angola (FNLA) guerrillas, who dubbed them "Elefante Dundum".

[47] Period photographs show some modifications to the basic design, namely the omission of the bow machine gun, re-installed on a pintle mount in the roof of the turret, and a small searchlight fitted in front of the commander's cupola.

[48] During the four-day long Football War of 1969, El Salvador invaded Honduras in an all-out-war strike using the M3 Stuart as the main battle tank.

[49] The M3 Stuart is still on the active list in the Armed Forces of Paraguay, with ten of the tanks being overhauled in 2014 to provide a training capability.