The hull floor ranged from thick at the front to thick at the rear. The glacis plate of the M8 was sloped at 45 degrees from the vertical and was thick. The upper hull sides, like the lower hull sides, were vertical and thick at the front, thinning to thick at the rear. The upper rear hull was a vertical plate, . The plate sloped at 50 degrees for a short distance before it met the hull roof, which was uniformly thick, and flat. The turret of the M8 was of cast steel. It was thick at the front, which was rounded, sloping from 0 to 63 degrees from the vertical. The sides and rear were thick and sloped at 20 degrees from the vertical. The cast gun shield, which covered the barrel of the 75 mm Howitzer M2/M3, was thick and rounded. The armament of the M8 consisted of a new open-topped turret armed with a 75 mm M2 howitzer, later a 75 mm M3 howitzer. The M8 carried 46 rounds of 75 mm ammunition; 11 rounds at the right rear of the fighting compartment, 20 rounds at the left rear of the fighting compartment, 9 rounds in the left hull sponson, and 6 "ready" rounds stored between the driver and assistant driver's positions. The most common types of ammunition carried were the M89 white phosphorus shell and the M48 high explosive shell. Unlike the standard M5 light tank, the M8 featured no hull-mounted or coaxial Browning M1919A4 .30 caliber machine gun. A Browning M2HB .50 caliber machine gun with 400 rounds was mounted on the right rear corner of the turret for local defense and anti-aircraft purposes. For self-defense, the vehicle driver was provided with a Thompson submachine gun, while the other three crew members were issued M1 carbines.  1,778 of the Howitzer Motor Carriage M8 were produced by the Cadillac division of General Motors from September 1942 to January 1944. M8's were issued to Headquarters companies in medium tank battalions in Europe. Starting in 1944 they were replaced by the 105mm howitzer variant of the M4 Sherman tank. The 75 mm Howitzer Motor Carriage M8 was assigned to the Assault Gun Troops of Cavalry Reconnaissance Squadrons in order to give them close support against enemy fortified positions. The high elevation (40 degrees) of the howitzer was useful for hitting enemies emplaced on the sides of hills.