The 105 mm M2A1 (M101A1) howitzer was a howitzer developed and used by the United States. It was the standard U.S. light field howitzer in World War II and saw action in both the European and Pacific theaters. Entering production in 1941, it quickly gained a reputation for accuracy and a powerful punch. The M101A1 fired 105 mm high explosive (HE) semi-fixed ammunition and had a range of 11,270 meters, or 12,325 yards, making it suitable for supporting infantry.
All of these qualities of the weapon, along with its widespread production, led to its adoption by many countries after the war. Its ammunition type also became the standard for many foreign countries' later models.
The gun fired semi-fixed ammunition, with 105mm Cartridge Case M14. The propelling charge consisted of a base charge and six increments, forming seven charges from 1 (the smallest) to 7 (the largest). Use of M1 HE rounds prepared for the 105mm howitzer M3 (same projectile and cartridge, but different propelling charge) was authorized.
HEAT M67 Shell was originally designed as fixed round, with Cartridge Case M14 type II. It was later changed to semi-fixed type with the standard cartridge, but with non-adjustable propelling charge. For blank ammunition, a shorter Cartridge Case M15 with black powder charge was used.

Manufacturer - Rock Island Arsenal
Produced - 1941–1953
Specifications
Weight - 2,260 kg (4,980 lb)
Length - 5.94 m (19 ft 6 in)
Barrel length - 2.31 m (7 ft 7 in) L/22
Width - 2.21 m (7 ft 3 in)
Height - 1.73 m (5 ft 8 in)
Shell - 105x372R
Caliber - 105 mm (4.1 in)
Breech - horizontal block
Recoil - hydropneumatic, constant, 42 in (110 cm)
Carriage - split trail
Elevation - -5° to +66°
Traverse - 46°
Muzzle velocity - 472 m/s (1,550 ft/s)
Maximum firing range - 11,270 m (7.00 mi)