TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
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TM 9--2350--311--10 5--66 Change 5 5--8 LOADING AND FIRING The chief-of-section must ensure that the following duties and actions are accomplished by the crew on each and every round loaded and fired from the cannon tube. WARNING • Observe all precautions in AR 385--63, FM 6--40, and FM 6--50, particularly limitations regarding overhead fire in training and combat to prevent injury to personnel. • Do not load or fire artillery ammunition without the authorized fuze to prevent death or injury to personnel. Firing of such rounds without fuzes or with an unauthorized fuze could result in inbore prematures and other hazardous conditions. • Do not load or fire round if the fuze is not fully seated to prevent death or injury to personnel. • Firing the M557, M572, and M564 fuzes during heavy precipitation (heavy rainfall, sleet, snow, or hail) may result in occasional downrange prematures causing injury to personnel. The amount of precipitation necessary to cause functioning is comparable to the heavy downpour which occurs during a summer thunderstorm. • Do not fire M110 series WP projectiles which are known to have been stored in other than the base down position. Firing of such projectiles could contribute to inbore prematures or close-in premature malfunctions resulting in death or injury to personnel. • Do not fire proximity-fuzed ammunition at targets closer than 765.53 yards (750 m) to friendly troops to prevent injury to personnel. • Firing the M100 series, M485, or M804/M804A1 projectiles at charge 2 may occasionally result in stickers causing death or injury to personnel. • Do not fire the M483A1, M692, M731, M718, M718A1, M741, M741A1, M825, M687, or M864 projectiles below charge 3. Firing below charge 3 may result in stickers causing death or injury to personnel. • MK399 MOD 1 fuzes in the delay mode perform more effectively if the angle of attack (angle between the round and the perpendicular of the target) is less than 45 degrees. Angles of attack higher than 45 degrees will result in decreased effectiveness and increase the likelihood of unexploded ordinance in the battlefield. • If a projectile fired with MK399 MOD 1 fuze impacts a substantial object, a higher order detonation may occur even if the object is within the 400 caliber minimum firing distance, which could result in damage to the weapon and/or death or serious injury to unprotected crew members.