TM-9-2350-311-34-2 Maintenance Manual for Volume 2 M109 Cab Download
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TM 9-2350-311-34-2 5-4 CANNON TUBE - CONTINUED c. Installation - Continued An incorrect fit and/or thread damage may allow propellent gases to leak into crew compartment when cannon assembly is fired or may cause failure of the breech assembly. Do not attempt to lock cannon tube into breech by turning 45 degrees unless all three fit indications have been checked. Attempting to rotate an improperly fitted cannon into locked position can result in damage to the breech or cannon threads that will not be detectable by visual inspection. 12 To ensure proper fit of cannon tube (5) and breech ring (9), inspect inner breech ring surfaces. Rear face of cannon tube must be flush with rear shoulder of breech ring (Y). Distance from rear face of cannon tube to rear face of breech ring (Z) must be no more than five inches (12.7 cm). 13 Inspect cannon tube (5) at front face of breech ring (9). Machined end of cannon tube should not show if cannon tube is properly installed in breech ring. There should be no gap between front face of breech ring and the facing cannon tube. 5-32