10/21/2026
We're back with another ...or should we say' "Weapons," plural.
One of the more obscure vehicles the Marines took into combat during the Vietnam War was designed during the Korean War and based on the M46/M47 tank design. Instead of having a centrally-mounted turret designed for antitank and infantry support work, the M53 and M55 self-propelled howitzers took the basic hull design, rotated it 180-degrees and mounted a massive turret and spade on the back end. Two guns were planned for the new vehicle, both using the same mount, so they could be used interchangeably if necessary. The M53 155mm self-propelled gun and M55 8-inch self-propelled howitzer each brought different capabilities to the same chassis; one with greater range and the other with greater firepower.
Unlike the Army, which only selected the M55, the Marine Corps utilized both types in service starting in the late 1950s. When the Vietnam War escalated to include US combat troops in the summer of 1965, the M53 and M55 were nearing obsolescence, but were Corps-level assets needed to support combat operations. The 1st, 3d, and 5th 155mm Gun Batteries and 1st and 3d 8-inch Howitzer Batteries provided long range fire support in I Corps through 1968 before both types were phased out in favor of the M107 175mm self-propelled gun.
The Museum collection has both an M53 and M55 in the permanent collection, both of which are on exhibit out at MCAGCC Twentynine Palms along the PT track. Both guns histories are unclear, but we do know that M55 333749 was rebuilt in Utah in October 1966. It may have served in Vietnam prior to that. We do know its sister guns 333744 and 333746 both saw combat with the 1st 8-inch Howitzer Battery in 1967. M53 213154 has a similarly mysterious history.
Both guns are the last of their kind within the Marine Corps. If anyone has information pertaining to either of these guns' service history, please reach out. Any information you can contribute on the service history of both of these massive guns will be greatly appreciated!
