- M1 Mortar
World War II.] The M1 is a United States81 millimeter calibre mortar. It was used during the World War IIwell into the 1950s when it was replaced by the lighter and longer ranged M29 Mortar. It was based on the French Brandt mortar.
* Weight assembled: 136 lb (61.5 kg)
**Tube 44.5lb (20kg)
**Mount 46.5lb (21kg)
**Base plate 45lb (20.5kg)
* Overall length: 3ft 9.5in (1.21 m)
* Muzzle velocity (HE): 700 fps (213 m/s)
* Rate of fire:
**18 round/min sustained
**30-35 round/min maximum
* Maximum range (HE): 3,290 yd (3,008 m)
* Sight: M4
*M43A1 Light HE: 6.87 lb (3.11 kg); range min 200 yd (183 m); range max 3290 (3008 m); 80% frag radius 25 yd (23 m) (comparing favorably with 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 with 105 mm howitzer; equipped with delay fuze so some penetration possible for demolition use.
*M56 Heavy HE: 15.01 lb (6.81 kg); range max 1300 yards (1189 m); 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 candela) 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 illum and chute.
* [http://www.90thidpg.us/Equipment/Weapons/index.html 90th Infantry Division Preservation Group] - page on 81mm Mortars and Equipment
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