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PROJECTILE, 155-MILLIMETER ILLUMINATING, M485 SERIES |
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Filler and Weight | ||
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| IIIum Compound, | |||
| Body and Overall Weight | |||
| Forged steel, 92.lb nom | |||
| Color | |||
| Olive drab w/white marking | |||
| Type of Round, DODIC | |||
| IIIum, 1320-D505 |
| Description: |
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| The projectile is a hollow steel shell containing an illuminant canister, a canister expelling charge in the nose, and a drogue parachute in the base. The illuminant canister contains the main parachute and lines, the illuminant candle assembly, a secondary expelling charge and a delay element holder. The outer shell of the canister is fitted with four longitudinal fins. The fins extend under spin forces when the canister is ejected from the projectile. The base of the projectile is closed with a pressfitted steel plug retained by shear and twist pins. A gilding metal rotating band and a plastic obturating band encircle the projectile near the base and are protected by a grommet during shipment and handling. The projectile uses an MT type fuze. The fuze cavity is fitted with a lifting ring plug for shipment and handling. Model M4851A1 has both shear and twist pins retaining the base plug. Model M485 has only shear pins. Model M485A2 has perforated cansister fins to decrease the rate of deceleration before the parachute deploys. |
| Use: |
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| This projectile is fired from 155mm howitzers and is used to illuminate the battlefield at night or during other conditions of reduced visibility. |
| Functioning: |
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| When the weapon is fired, the rotating band engages the barrel rifling to impart spin to the projectile for stability in flight. The obturator band expands to prevent leakage of gas pressure past the projectile. The burning propellant charge reduces rapidly expanding gases to propel tRe projectile through the barrel with the velocity required to reach the desired point of function. When the fuze functions, the primary expelling charge ignites forcing the drogue parachute and canister assembly against the base plate, rupturing the base pins and expelling the canister and parachute. The drogue parachute then deploys, and the canister fins extend. These actions combine to decelerate the canister and stop rotation, The expelling charge also ignites the delay element in the canister nose, The delay element ignites the secondary expelling charge within the canister after 8 seconds when velocity has been safely reduced. The secondary expelling charge then ignites the candle illuminate, and expels the main parachute and candle loading assembly. with the main parachute open, the illuminant candle descends at 15 fps and burns for 120 seconds roducing approximately 1,000,000 candle-powder. |
| Munition Components: |
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| Data Source: |
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| TM 43-0001-28 April 1977 |
| Munitions Tech Data Sheet: |
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