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 3--50 Change 6 3--6 ARMAMENT AND CAB MAINTENANCE — CONTINUED 3--6.5 Estimating Remaining Round Life of Cannon Tubes Cannon tubes must be inspected and borescoped within 180 days prior to initial firing and within each 180 day interval when utilized for continuous or recurring firing. Notify unit maintenance for borescoping (TM 9--1000--202--14). WARNING Do not fire beyond cannon tube life. NOTE • Condemnation of the cannon tube is based on fatigue life in Equivalent Full Charge (EFC) rounds or wear life (pullover gauge measurement), whichever occurs first. • Breech assemblies which have been modified from the M185 cannon assembly to the M284 cannon assembly may have EFC condemnation criteria stamped on the breech assembly and DA Form 2408--4. The method for determining remaining life for cannon tubes is to convert rounds fired to Equivalent Full Charge (EFC) rounds. Convert to EFC rounds and enter in Weapon Record Data DA Form 2408--4 in accordance with DA Pam 750--8. Since the condemnation criteria as listed in the table below is based on EFC rounds fired, the zone for each round fired must be entered on DA Form 2408--4, and the total rounds fired by zone must be carried forward to the new data card upon closeout in accordance with DA Pam 750--8. Condemnation Criteria for Cannon Tube and Breech Assembly Model No. EFC Life of Cannon Tube EFC Factor Breech Assembly Life M185 6375 rds Zone 1--6 = 0.25 Zone 7 = 0.75 Zone 8 = 1.00 Original and two retubings M284 2650 rds Zone 1 (M231) = 0.05 Original with one retubing Zone 2 (M231) = 0.15 Zone 3 (M232/M232A1) = 0.10 Zone 4 (M232/M232A1) = 0.25 Zone 5 (M232/M232A1) = 1.00 Zone 3G--5G (3A1) = 0.05 Zone 3W--6W (M4A2) = 0.05 Zone 7W (M4A2) = 0.15 Zone 8/7R (M119A1/A2) = 0.25 Zone 8R/8S (M203/A1) = 1.00