TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
Page 285 of 775
TM 9--2350--311--10 Change 6 2--187 2--12 PREPARATION FOR FIRING — CONTINUED 2--12.2 Boresighting — Continued f. Comparison Test of the M140/M140A1 Alinement Device — Continued 2 Install a second M140/M140A1 alinement device (27). If using ERLS version, depress button (36.1) to activate. Without moving position of M117/M117A2 panoramic telescope (18), view through eyepiece (37). If M117/M117A2 panoramic telescope reticle and M140/M140A1 alinement device reticle aline, you have verified accuracy of M140/M140A1 alinement device. 3 If M117/M117A2 panoramic telescope (18) reticle and second M140/M140A1 alinement device (27) reticle do not aline, or if azimuth counter (19) reading is not correct after reticles are alined, one of two M140/M140A1 alinement devices is unserviceable.