Description
U.S. Army Technical Manual TM 9-1240-346-35P for M21A1 Telescope Mount, March 1970
Item Overview
This original U.S. Army technical manual is the direct-support, general-support, and depot-maintenance repair-parts reference for the M21A1 Telescope Mount. Issued as TM 9-1240-346-35P in March 1970, it helped maintenance and supply personnel identify and order components for this field-artillery fire-control mount. This listing is for the technical manual only. It does not include an M21A1 mount, telescope, howitzer, or other sighting equipment.
Identification and Features
The “35P” suffix identifies this as a higher-level repair-parts and special-tools publication. It focuses on illustrated parts identification and supply information rather than complete operating or repair procedures.
- Manual number: TM 9-1240-346-35P
- Publication date: March 1970
- Subject: M21A1 Telescope Mount
- Official item name: Mount, Telescope
- Part number: 7578396
- Federal Stock Number: 1240-757-8596
- Later National Stock Number: 1240-00-757-8596
- Federal Supply Class: 1240, Optical Sighting and Ranging Equipment
- Manual type: Repair parts and special tools list
- Maintenance levels: Direct support, general support, and depot maintenance
- Supported telescope: M12A7-series panoramic telescope
- Primary weapon application: M101/M101A1 105mm Light Towed Howitzer
- Issuing authority: Headquarters, Department of the Army
- Country of origin: United States
- Item included: Technical manual only
Manual Coverage
This publication supports parts identification, requisitioning, and higher-level maintenance of the M21A1 mount. Manuals of this type normally contain exploded illustrations, item numbers, official part names, stock and manufacturer numbers, quantities, maintenance codes, supply codes, and special-tool information. It is especially useful when matching loose components to their correct locations in the mount assembly.
How the M21A1 Mount Worked
The M21A1 held and supported an M12A7-series panoramic telescope used for indirect artillery fire. Its socket secured the telescope while longitudinal and cross-leveling mechanisms allowed the sight to be leveled with the weapon. This stable and adjustable platform helped the gunner measure direction, set deflection, and accurately lay the howitzer on targets that could not be seen directly from the gun position.
Weapon-System Application
The M21A1 was part of the fire-control equipment used on the M101 and M101A1 105mm Light Towed Howitzers. The panoramic telescope and M21A1 mount supported indirect fire, while related equipment such as the M16A1D elbow telescope and M23 mount supported direct-fire aiming. Together, these instruments allowed the howitzer crew to engage visible targets or fire at targets located beyond hills, trees, buildings, and other obstructions.
Historical Background
The M101A1 developed from the M2A1 105mm howitzer used by the United States during World War II. The weapon continued serving through the Korean War and was redesignated M101A1 during the early 1960s. It remained widely used during the Vietnam War because it was reliable, mobile, and capable of providing effective fire support from prepared positions or remote firebases. The M21A1 mount supported this long-serving weapon by keeping its panoramic telescope stable and correctly leveled.
History of Use
M101-series howitzers served with U.S. Army, Marine Corps, National Guard, and allied artillery units. Crews used the weapon for high-explosive, smoke, illumination, and other fire missions. Although newer 105mm systems later replaced it in much of U.S. service, the M101A1 continued operating with many allied countries for decades. The March 1970 manual reflects the Army’s need to maintain established fire-control equipment during the Vietnam era.
Condition
Please check the pictures for the general condition of the item. This listing is for one TM 9-1240-346-35P technical manual only; the M21A1 mount, M12A7-series telescope, M101-series howitzer, and other equipment are not included.
Ideal For
This specialized publication is useful for collectors, restorers, museums, and researchers studying U.S. field-artillery sights and the M101-series 105mm howitzer.
- U.S. Army technical-manual collections
- M21A1 telescope-mount restoration
- M12A7 panoramic-telescope research
- M101 and M101A1 howitzer displays
- 105mm field-artillery collections
- Vietnam War artillery exhibits
- Military fire-control equipment research
- Museum and archival collections
Approx length 8", Approx width 11", Approx height .2", Approx weight .3lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item’s general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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