4.5-inch Gun M1

The 4.5 inch Gun M1 was a field gun developed in the United States in the beginning of World War II. It shared the same carriage with the 155mm Howitzer M1 and fired the same ammunition as the British BL 4.5 inch Medium Field Gun. The weapon was used by the US Army in Northwest Europe late in the war for corps support; with the end of hostilities it was declared obsolete.

Country Name Origin Year
United States of America 1942
Country Name Operational Year Retirement Year
United States of America 1942 1945 View

In 1920 the US Army Ordnance started to work on a new medium field gun. Since the US Army had already employed the 4.7 inch Gun Model 1906 during World War I, this caliber was also selected for the new weapon. The development resulted in 4.7 inch Gun M1922E on Carriage M1921E. Due to lack of funding, the design never reached production.

In 1939 the program was restarted; the renewed design, designated 4.7 inch Gun T3, was ready by early 1940; it utilized the same carriage as the concurrently developed 155 mm howitzer. At this stage, the army decided to change the weapon to use the British 4.5 inch ammunition. The modified gun was standardized in April 1941 as 4.5 inch Gun M1 on Carriage M1.

The M1 equipped 16 or 17 field artillery battalions in the Northwest Europe, where it was employed for corps support. M5 High Speed Tractor was assigned as prime mover. The weapon was declared obsolete in September 1945.

The gun had good range, nearly five km longer than its 155 mm howitzer sibling and longer than the 155 mm Gun M1918MI. It was out-ranged by another 155 mm gun, the Long Tom, but the latter was nearly three times heavier.

On the other side, the 4.5 inch gun was criticized for insufficient power of its high-explosive shell. The shell was produced from low grade ("19 ton") steel, which necessitated thick walls. As a result, it carried only about two kg of TNT or substitute, in fact less than the 105 mm high explosive shell. Additionally, it was felt that having a small number of guns of atypical caliber unnecessarily complicated logistics.

Type Field gun
Place of origin USA
Service history
In service 1942-1945
Used by USA
Production history
Designed 1939-1941
Produced 1942-44
Number built 416
Weight 5,654 kg (12,465 lbs)
Length 8.15 m (27 ft)
Barrel length Bore: 4.756 m (15 ft 7 in) L/41.6
Overall: 4.918 m (16 ft 2 in) L/43
Width 2.4 m (7 ft 10 in)
Height 2.12 m (6 ft 11 in)
Shell separate-loading bagged charge
Caliber 114 mm / 4.5 inch
Breech interrupted screw
Recoil hydropneumatic
Carriage split trail
Elevation 0° to +65°
Traverse 53°
Rate of fire Burst: 4 rounds per minute
Sustained: 1 round per minute
Muzzle velocity 693 m/s (2,274 ft/s)
Maximum firing range 19,317 m (21,125 yds)
Sights panoramic, M12

End notes