TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
Page 269 of 775
TM 9--2350--311--10 2--171 2--12 PREPARATION FOR FIRING — CONTINUED 2--12.2 Boresighting — Continued a. Preliminary Procedure — Continued 5 Use M1A1 gunner’s quadrant (5) that has been checked by micrometer test and end-for-end test (para 3--7.2). Level gun trunnions as follows. (u) Set index arm (6) and micrometer knob (7) to zero. (v) Set M1A1 gunner’s quadrant (5) with end-for-end correction applied on cross-level seats (8) on breech ring. (w) Traverse howitzer until bubble (9) centers (test target method only). 6 Set cannon tube at zero elevation (para 3--7.5). 7 Center bubbles in pitch level (10) and cross-level (11) of M145/M145A1 telescope mount (12). 5 6 7 8 9 10 11 12