M1 mortar

U.S. Soldiers fire an M1 mortar at Massa in Italy during World War II
Type	Infantry mortar
Place of origin	United States
Service history
Used by	United States
Wars	World War II, Korean War
Specifications
Mass	see general data
Length	3 ft 11 in (1.19 m)
Caliber	81 millimetres (3.2 in)
Rate of fire	18 rpm sustained 30-35 rpm maximum
Muzzle velocity	700 ft/s (210 m/s)
Effective firing range	3,300 yd (3,000 m)
Sights	M4

The M1 mortar is an American 81 millimeter caliber mortar. It was based on the French Brandt mortar. The M1 mortar was used from World War II until the 1950s when it was replaced by the lighter and longer ranged M29 mortar.

General data

Weight:

• Tube 44.5 lb (20 kg)
• Mount 46.5 lb (21 kg)
• Base plate 45 lb (20 kg)
  • Total 136 pounds (62 kg)

Ammunition

• M43A1 Light HE: 6.87 lb (3.11 kg); range min 200 yd (183 m); range max 3290 yd (3010 m); 80% frag radius 25 yd (23 m) (compared favorably with the 75 mm howitzer); fast detonating fuze (explode on surface).

• M45, M45B1 Heavy HE: 10.62 lb (4.82 kg); range max 2558 yd (2064 m); bursting radius comparable to the 105 mm howitzer; equipped with delay fuze so some penetration is possible for demolition use.

• M56 Heavy HE: 15.01 lb (6.81 kg); range max 1300 yards (1200 m); had an adjustable fuze for quick or delay operation.

• M57 WP (White phosphorus): 10.74 lb (4.87 kg); range max 2470 yd (2260 m); designed to lay down screening smoke, but had definite anti-personnel and incendiary applications.

• M57 FS: 10.74 lb (4.87 kg), range max 2470 yd (2260 m); laid down dense white smoke.

• M301 Illuminating shell: range max 2200 yd (2012 m); attached to parachute; burned brightly (275,000 candelas) for about 60 seconds, illuminating an area of about 150 yards (137 m) diameter; used M84 time fuze, adjustable from 5 to 25 seconds before priming charge detonated, releasing the illuminator and chute.

See also

• List of U.S. Army weapons by supply catalog designation SNL A-33
• M3 Half-track

References

• FM 23-90
• TM 9-1260
• SNL A-33

External links

• 90th Infantry Division Preservation Group - page on 81 mm mortars and equipment
• Popular Science, August 1943, Pill Boxes Destroyer article on M1 81mm mortar