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--18 Change 6 Table 5--1. 155MM AMMUNITION FOR M109 HOWITZERS — CONTINUED Authorized Projectiles Remarks Fuzes Identification Classification M549, M549A1, HERA WARNING • The M549 and M549A1 projectiles are not to be fired if the obturator is missing or broken as rotating band failure and short round may result. If the band is displaced and can be repositioned and remain in the groove, the projectile can be fired. The basic M119 charge is not to be used with the M549 and M549A1 projectiles as its use will result in rocket motor ignition failure, causing loss of range (short rounds). Use M119A1 or M119A2 charges. • Standard procedures prohibit firing the M549/M549A1 in the rocket off mode except in combat emergencies. Remove rocket cap before loading to activate rocket. • A 7000--meter safety zone is required short of the target because of the possibility of rocket motor non--ignition. • If fired, in the rocket off mode, due to emergency situation, a 7000--meter range is required beyond the target because of the possibility of rocket motor ignition. • The M549 projectile may not be fired with the M203 propelling charge. The M549A1 projectile may be fired with the M203 propelling charge. NOTE • The protective rocket motor cap must be removed from the projectile before firing to increase the range over that attainable ballistically. • The M549 projectile differs from the M549A1 projectile only in the type of explosive filler. The M549 projectile is loaded with composition B and the M549A1 projectile is loaded with TNT. • The M549 and M549A1 projectiles have the energy-absorbing or shock attenuating lifting plug designed to protect the projectile fuze area against accidental damage. The new plug has an oversized 3-3/4 inches (9.53 cm) flange. If this lifting plug is broken at the neck area, the threaded portion of the plug will remain in the projectile and the projectile cannot be fuzed. No attempt should be made to extract any portion of a broken plug from a projectile. The projectile is not to be used and should be returned to battalion ammunition section. • The M549/M549A1 projectile may break--up upon impact with urban structures and bunkers rendering it an ineffective penetrator of these targets. • Refer to the description of the MK399 MOD 1 fuze in paragraph 5--2.2a for expected performance against MOUT targets.