M109 155mm Artillery
This is a 155 MM self propelled howitzer. To the layman it may appear to
be a tank, but it was not. The howitzer was an artillery weapon which
lobbed shells through indirect fire over a long range, as opposed to tanks
which used their main gun for direct fire at targets which they could see.
The 155 MM howitzer was the workhorse of indirect fire support for us, able
to fire high explosive (HE), white phosphorous (WP), illumination, and
The M109A4 and M109A4+ are fully tracked, armored vehicles used to provide close artillery support. The vehicles are air-transportable and carry a
total of 36 rounds. The howitzer was a common sight at firebases in Vietnam and could be relocated for close in support.
The howitzer was usually accompanied by armored cavalry or armored units. The 155mm cannon is designated the (M185). The assembly comprises a breech ring, bore evacuator, muzzle brake and a tube
cannon. The breech mechanism is a semi-automatic, screw block type, designated for separate loading ammunition. Breech opening and closing is
accomplished by utilizing the energy of counter recoil and closing, by laminated torsion springs.
Firing is accomplished by the mechanism (M35) which
uses cartridge type primers, fired by a continuous pull percussion mechanism. The mount consists of a cradle assemble that mounts the hydraulic
variable recoil mechanism, S.A. cam, recuperator, counter recoil buffer, upper and lower rotors, limit stops and dust shields. Pad and brackets are
available for mounting the fire control instruments.
"I remember one time working west of Quang Tri we escorted three M109's out into the field. It was a pretty awesome sight; armored cav and some really big guns. I was still on the mortar track so I was in the middle of the perimeter at the NDP. Everything was really great. I was sleeping comfortably on top of track 29 when the howitzers had a fire mission. One of the barrels was directly over my track so when they touched off the first round I was lifted off the deck. My ears still ring to this day. It was one of my last times on the mortar track. I transferred to a scout track after that."
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