Description
Technical Manual (TM 9-1240-295-35) for M138 Telescope Mount December 1962
U.S. Army Technical Manual TM 9-1240-295-35 for M138 Telescope Mount, December 1962
Item Overview
This U.S. Army technical manual covers field-and-depot maintenance for the M138 Telescope Mount. Issued as TM 9-1240-295-35 in December 1962, it was prepared for trained personnel responsible for servicing this specialized artillery fire-control component.
This listing is for the technical manual only. It does not include an M138 mount, elbow telescope, elevation quadrant, artillery weapon, tools, or other equipment.
About the M138 Telescope Mount
The M138 was designed to hold an elbow telescope used for direct artillery fire. Early configurations supported the M116 and M116C Elbow Telescopes. The mount was later used with the M139 Elbow Telescope on updated M110A2 equipment.
The mount includes a support assembly, telescope clamp, bracket assembly, and adapter. Adjustment mechanisms allow the telescope’s elevation and deflection to be set and locked in position.
The bracket also contains an electrical system for illuminating the attached telescope. Vehicle power allowed the sight to be used during low-light and nighttime operations.
Documented Artillery Applications
The M138 mount was used with the M107 175-mm Self-Propelled Gun and M110 8-inch Self-Propelled Howitzer families.
On the M107, the M116C telescope and M138 mount formed part of the right gunner’s direct-fire sighting equipment. The telescope provided the sight picture, while the mount positioned and supported the optical instrument. This equipment worked with the M15 Elevation Quadrant to help the crew aim the weapon.
Historical Background
TM 9-1240-295-35 was published as the U.S. Army introduced a new generation of tracked heavy artillery. The M107 and M110 entered service during the early 1960s and later saw combat during the Vietnam War.
Direct-fire optics allowed crews to aim at visible targets when battlefield conditions required it. Proper alignment was critical because movement or wear inside the mount could shift the telescope and reduce accuracy.
The continued use of the M138 on later M110 equipment shows the lasting value of its basic design. This December 1962 manual documents the mount near the beginning of its long military service.
Publication Details
- Manual number: TM 9-1240-295-35
- Publication date: December 1962
- Subject: M138 Telescope Mount
- Federal Stock Number: 1240-896-2240
- Later NSN format: 1240-00-896-2240
- Part number: 8587500
- Manual type: Field-and-depot maintenance
- Original associated telescopes: M116 and M116C Elbow Telescopes
- Later associated telescope: M139 Elbow Telescope
- Documented artillery systems: M107 and M110 families
- Primary role: Direct-fire telescope support and adjustment
- Item included: Technical manual only
Collector and Research Value
This manual is a specialized addition to a U.S. Army technical-publication, artillery, or military-optics collection. It provides useful information about maintaining a precision sight mount used with major Cold War artillery systems.
It is also suitable for museums, restorers, historians, and collectors researching the M138 mount, M116C telescope, M107 gun, or M110 howitzer.
Ideal For
- U.S. Army technical-manual collections
- M138 telescope-mount maintenance research
- M107 and M110 artillery displays
- Cold War and Vietnam War collections
- Military-optics restoration references
- Museum and archival collections
Approx length 8", Approx width 10", Approx height .2", Approx weight .2lbs.
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