Description
U.S. Army Technical Manual TM 9-1240-319-35 for M148 Telescope Mount, 1967
Item Overview
This U.S. Army technical manual covers higher-level maintenance for the M148 Telescope Mount. Issued as TM 9-1240-319-35 in 1967, it supported military personnel responsible for inspecting, repairing, adjusting, and testing this fire-control component. The M148 held the M120 straight telescope in direct-fire sighting systems for 20mm weapons. This listing is for the technical manual only. It does not include an M148 mount, M120 telescope, instrument light, weapon, vehicle, or other equipment.
Identification and Features
The “35” suffix identifies this as a direct-support, general-support, and depot-maintenance publication. Manuals at this level were intended for trained personnel performing work beyond routine operator and organizational maintenance. The available identification data connects the listed Federal Stock Number with the M148 telescope mount and its official Army drawing.
- Manual number: TM 9-1240-319-35
- Publication year: 1967
- Subject: M148 Telescope Mount
- Official item name: Mount, Telescope
- Manual type: Direct-support, general-support, and depot-maintenance manual
- FSN: 1240-930-4258
- Later NSN: 1240-00-930-4258
- Federal Supply Class: 1240, Optical Sighting and Ranging Equipment
- Army drawing number: 10543453
- Associated telescope: M120 straight telescope
- Associated instrument light: M52-series instrument light
- Related military specification: MIL-M-60544A
- Issuing authority: Headquarters, Department of the Army
- Country of origin: United States
- Item included: Technical manual only
How the M148 Telescope Mount Worked
The M148 provided a stable connection between the M120 telescope and a weapon mounting system. Its dovetail and clamping mechanism allowed the telescope to be attached or removed quickly. Separate elevation and azimuth controls allowed maintenance personnel to align the telescope’s line of sight with the weapon bore. Clamping screws held the completed boresight adjustments in place. Military specifications also required the mount to resist shock, vibration, and storage temperatures ranging from approximately -80°F to 160°F without physical failure.
Telescope and Weapon Applications
The M148 was designed to support the M120 straight telescope as part of a direct-fire sighting system for 20mm guns installed on armored carriers and other ground-mounted weapons. The M120 was a fixed 6-power telescope with an approximately 92.5-mil field of view. An M52-series instrument light illuminated its reticle for low-light aiming. A documented application placed this sighting equipment on the gun cradle of the M114A1E1, later standardized as the M114A2, where it supported the M139 20mm automatic cannon in the XM27 powered cupola.
Historical Background
The M148 was developed during the Cold War as the U.S. Army tested stronger armament for light reconnaissance vehicles. MIL-M-60544A, dated January 1967, established requirements for the M148 and a related experimental mount. The manual dates from this development period and predates the later M114A1E1 20mm vehicle installation. The M114 family began as a compact, amphibious command-and-reconnaissance carrier. Early models used a .50-caliber machine gun, while the M114A1E1 and M114A2 received the more powerful M139 20mm cannon. The M114 family saw early service in Vietnam, but the first versions were withdrawn from that theater after proving poorly suited to local terrain. The family continued serving with U.S. Army units during the 1970s, making this manual an important record of its later fire-control development.
Condition
Please check the pictures for the general condition of the item. This listing is for one TM 9-1240-319-35 technical manual only; the telescope mount, sight, instrument light, weapon system, vehicle, and other accessories are not included.
Ideal For
This manual is well suited for collections and research projects covering Cold War fire-control equipment, armored reconnaissance vehicles, and U.S. Army maintenance publications.
- U.S. Army technical-manual collections
- M148 telescope-mount research
- M120 straight-telescope restoration references
- M139 20mm weapon-system research
- M114A1E1 and M114A2 vehicle displays
- Cold War military-optics collections
- Vietnam-era armored-vehicle exhibits
- Museum and archival collections
Approx length 8", Approx width 10", Approx height .2", Approx weight .2lbs.
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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