Description
TM 9-3064 Change 4 - 81mm M29E1 Cannon on M23A3 Mount and M29 or M29E1 Cannon on M23A1 Mount - June 1967
Item Overview
This June 1967 Change 4 supplement updates TM 9-3064 for the 81mm M29 mortar family and its M23A1 and M23A3 mounting configurations. It is intended for use with the original manual issued on August 15, 1957. This Vietnam-era publication is a useful addition to a collection of infantry weapons manuals, mortar references, or military maintenance records.
Identification and Features
The publication number, change designation, and equipment combinations help identify the correct supplement for a technical reference set.
- Publication: TM 9-3064, Change 4
- Change date: June 1967
- Original manual date: August 15, 1957
- Caliber: 81mm
- Covered configurations:
- M29E1 cannon on M23A3 mount.
- M29 or M29E1 cannon on M23A1 mount.
- Manual category: Operation and organizational maintenance
- Publication type: Change supplement for the base manual
Function and Manual Contents
Change 4 revises material in the Army's operation and organizational maintenance reference for these mortar assemblies. The parent manual addresses operating guidance, lubrication, and maintenance assigned to the unit using the equipment. Reading the supplement alongside the base publication keeps its revisions connected to the instructions available to mortar crews and unit maintenance personnel.
Publication History
The original TM 9-3064 carried the earlier publication number TM 9-260 on its cover. This fourth change appeared nearly ten years after the 1957 base edition, during the Vietnam War. Such supplements kept established manuals in use as technical guidance changed. For collectors, this update documents the continuing support of the M29 family and its different mounting arrangements.
Documented End-Item Application
This update covers the M29E1 cannon on the M23A3 mount, plus either the M29 or M29E1 cannon on the M23A1 mount. The cannon is the mortar's barrel assembly. The mount designation identifies the supporting equipment and associated baseplate arrangement, making the complete combination important when researching a period mortar setup.
Equipment History
The M29 began replacing the wartime M1 mortar in U.S. service in 1952. Its lighter construction and greater range advanced the Army's portable infantry fire-support equipment. Grooves around the cannon's exterior reduced weight and helped release heat. Continued development produced related cannon versions and mounting configurations while retaining the familiar barrel, bipod, and baseplate layout.
M23A1 and M23A3 Mount Background
The M23A1 and M23A3 belonged to a shared mount family already documented in Army field-maintenance literature by January 1958. Their bipods, elevating mechanisms, traversing mechanisms, and shock absorbers were grouped together for servicing. The bipod supported the cannon and carried the adjustment mechanisms, while the shock absorber helped manage movement during firing.
Baseplate Development
The baseplate supported the lower end of the cannon and spread firing forces into the ground. The M23A1 used a baseplate with separate inner and outer ring assemblies. Army references describe the M23A3 as retaining the M23A1 mount design while using a one-piece aluminum baseplate. This construction difference is a useful identification detail and an important part of the mount family's development.
Weapon-System Background
The M29 family used smoothbore, muzzle-loading cannons designed for high-angle fire. Their curved firing path supported infantry against positions behind terrain or cover. Separate cannon, mount, and baseplate assemblies allowed the weapon to be carried in component loads. The 81mm mortar continued an infantry support role established by earlier weapons such as the French Brandt-derived M1.
History of Use
The M29 family served U.S. and allied forces during the Cold War and Vietnam War. A 1967 field sketch preserved by the Australian War Memorial records an M29 mortar in a South Vietnamese Army bunker at Trieu Phong in Quang Tri Province. The family remained in service through later improvements, before the M252 began replacing it in U.S. service in 1987. This supplement belongs to the technical support history of those weapons.
Ideal For
This publication adds context to a mortar reference library and helps explain the relationship between cannon models, mounting equipment, and baseplate development.
- Collectors assembling a TM 9-3064 manual and change supplement set.
- Researchers studying M29 and M29E1 mortar development.
- Museums documenting M23A1 and M23A3 mounting equipment.
- Historians researching Cold War and Vietnam-era infantry support weapons.
- Military publication collectors comparing Army maintenance references over time.
Approx length 6", Approx width 9", Approx height .2", Approx weight .4lbs.
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