TM-9-2350-311-10
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; OPERATOR’S MANUAL
NOVEMBER 1994
TM-9-2350-311-10 - Page 72 of 775
TM 9-2350-311-10
1-14
EQUIPMENT OPERATION AND DESCRIPTION - CONTINUED
1-14.8
Mount and Howitzer Assembly
a. Tube Assembly/Cannon Assembly
1
2
3
4
5
CANNON TUBE. The cannon tube (1) serves as the chamber for the projectile. Rifled bore ensures
accurate projectile trajectory. Cannon tube mounts on inside of breech ring (2). Cannon tube locks inside
breech ring band (3) by means of interrupted threads and breech ring key (4).
BREECH RING KEY. The breech ring key (4) holds cannon tube (1) in correct position on breech ring
(2). The breech ring key prevents the cannon tube from turning and unlocking from interrupted threads.
BORE EVACUATOR. The bore evacuator (5) helps clear the cannon tube (1) of gases after firing,
minimizing the contamination of the air within the cab.
MUZZLE BRAKE. The muzzle brake (6) reduces the force of recoil and forward flash, and deflects
gases away from the cab.
THRUST COLLAR. The thrust collar (7) prevents the muzzle brake (6) from turning.
1-34
Back to Top
