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 490 of 775
TM 9-2350-311-10
3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED
3-7.3
Leveling Gun Trunnions
NOTE
Gun trunnions must be leveled to ensure the fire control equipment mounts are parallel with the
cannon tube. There are two ways to level gun trunnions: plumbline method and scribed lines
method.
a .
Plumbline Method
1 Attach crosshairs (1) made of fibrous twine (item 39, Appx D) at witness marks on muzzle brake (2).
2 Install breech bore sight (3) or remove firing pin and use firing pin hole for rear sight instead of breech
bore sight.
3-86
Back to Top
