Description
U.S. Army Technical Manual TM 9-1240-312-34 for M149 Telescope Mount, May 1973
This U.S. Army technical manual covers direct-support and general-support maintenance for the M149 Telescope Mount. Issued as TM 9-1240-312-34 in May 1973, it documents an important part of the fire-control system used on the M551 Sheridan.
This listing is for the technical manual only. It does not include an M149 mount, telescope, missile tracker, sighting equipment, weapon, or vehicle.
Manual Coverage
The “34” suffix identifies this as a direct-support and general-support maintenance manual. It was prepared for trained military personnel performing work beyond routine operator and organizational maintenance.
The publication supports the inspection, troubleshooting, repair, adjustment, optical alignment, testing, and servicing of the M149 Telescope Mount. This type of manual helped Army maintenance shops keep the mount correctly aligned with the telescope, missile tracker, and vehicle weapon system.
About the M149 Telescope Mount
The M149 was not a simple holding bracket. It was a sealed optical and mechanical assembly designed to support the M119 and M127 Articulated Telescopes. Its military part number was 10527950, and its National Stock Number was 1240-00-762-9334.
Installed coaxially with the M551 Sheridan’s 152mm gun-launcher, the mount held the gunner’s telescope and infrared missile tracker. An internal checksight system helped align the tracker with the telescope. The mount included ERROR and ALIGN controls, azimuth and elevation adjustments, optical components, electrical circuits, and a telescope-locking mechanism.
The optical section was sealed and filled with dry nitrogen to help prevent moisture and fogging. Military specifications required the mount to withstand vibration, extreme storage temperatures, and demanding operating conditions.
Fire-Control Application
The M149 mount formed part of a fire-control system designed for two types of weapons. The gunner used the articulated telescope when aiming conventional 152mm ammunition. The same sighting installation also supported the guidance system for the MGM-51 Shillelagh antitank missile.
The articulated telescope moved with the gun while keeping the eyepiece within reach of the gunner. Accurate alignment between the telescope, tracker, and gun-launcher was essential for both conventional fire and guided-missile operation.
Historical Background
The M551 Sheridan entered U.S. Army service in 1967 as a lightweight, amphibious, and air-transportable armored vehicle. It combined a 152mm gun-launcher with the MGM-51 Shillelagh guided missile, making its fire-control equipment more complex than the systems used on many earlier armored vehicles.
Sheridans entered combat in Vietnam in 1969 and later served with airborne and armored units. Published in May 1973, TM 9-1240-312-34 dates to the Vietnam War and early Cold War service period of the M551. It records the specialized maintenance required to keep the Sheridan’s optical and missile-tracking equipment working together.
Publication Details
- Manual number: TM 9-1240-312-34
- Publication date: May 1973
- Subject: M149 Telescope Mount
- National Stock Number: 1240-00-762-9334
- Military part number: 10527950
- Manual type: Direct-support and general-support maintenance
- Supported telescopes: M119 and M127 Articulated Telescopes
- Documented parent system: M551 Sheridan
- Weapon system: 152mm gun-launcher and MGM-51 Shillelagh missile
- Item included: Technical manual only
Collector and Research Value
This manual is a specialized addition to a U.S. Army technical-publication, military-optics, or armored-vehicle collection. It is useful for M551 Sheridan restoration research, M149 parts identification, museum exhibits, and the study of Vietnam War and Cold War fire-control systems.
Ideal For
- U.S. Army technical-manual collections
- M551 Sheridan restoration research
- M149 Telescope Mount maintenance research
- M119 and M127 telescope displays
- Vietnam War armored-vehicle collections
- MGM-51 Shillelagh fire-control research
- Museum and archival collections
Approx length 8", Approx width 11", Approx height .25", Approx weight .5lbs.
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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