tank chassis (M10A1s used an M4A3 chassis) with an open-topped manually traversed turret mounting the 3-inch gun M7, in the M5 mount. The M7 gun weighed 1,990 pounds. The gunner stood or sat on the left side of the gun, and aimed it using the M51 or M70G telescope. An M12A4 panoramic telescope was also provided on the right side of the turret for indirect fire use. The M10 carried 54 rounds of 3-inch ammunition, 48 of which were stowed in four racks in the sponsons, and 6 rounds in the upper rear of the turret. For combat use, the 3-inch Gun M7 could fire five types of ammunition: M79 AP-T shot M62/M62A1 APCBC/HE-T shell M42A1 high explosive shell M88 HC B1 (hexachloroethane smoke) shell T4 (M93) HVAP-T shot The M79 AP shot could penetrate 92 mm of homogeneous armor angled at 30 degrees from the vertical at 1,000 yards. The M62 APCBC/HE-T shell was capable of penetrating 88 mm of homogeneous armor angled 30 degrees from the vertical at 1,000 yards. The rare T4 (M93) HVAP shot that saw action in small numbers beginning in September 1944 was capable of penetrating 135 mm of homogeneous armor angled at 30 degrees from the vertical at 1,000 yards. This shot featured a sub-caliber tungsten carbide penetrator encased within a steel jacket and aluminum body and ballistic "windshield". It was standardized as the M93 in February 1945. By March 1945, about 18,000 rounds of this special ammunition had been delivered to the European Theater, 58 percent of which were 3-inch projectiles. The M42A1 high explosive shell was used for indirect artillery fire or against fortifications and soft targets like infantry in trenches or antitank guns. The M88 hexachloroethane smoke shell was used to create smoke screens, or to flush enemy infantry out of buildings or fortified positions. Secondary A .50 caliber (12.7 mm) Browning M2HB machine gun could be mounted on the top rear of the turret for use against enemy infantry and for anti-aircraft use, along with 300 rounds of ammunition stowed in 50-round boxes under the vehicle subfloor. The crew also had their personal weapons for self-defense. A Thompson submachine gun with 460 rounds of ammunition was stowed on brackets in the right rear of the turret for use by the vehicle commander. The other four crew members were armed with M1 carbines, each carrying as much ammunition on their