Description
U.S. Army Technical Manual TM 9-1240-317-35P for M104A1 and M104A2 Periscope Mounts, July 1970
Item Overview
This U.S. Army technical manual is the repair-parts and special-tools reference for the M104A1 and M104A2 Periscope Mounts. Issued as TM 9-1240-317-35P in July 1970, it helped military maintenance personnel identify and order components for these armored-vehicle sight mounts. This listing is for the technical manual only. It does not include a periscope mount, M28-series periscope, weapon, vehicle, or other optical equipment.
Identification and Features
The “35P” suffix identifies this as a direct-support, general-support, and depot-maintenance repair-parts and special-tools list. Manuals in this class commonly provided illustrated parts breakdowns, item numbers, Federal Stock Numbers, part numbers, quantities, supply codes, and maintenance reference data. This is a parts-identification manual rather than an operator’s guide or complete repair manual.
- Manual number: TM 9-1240-317-35P
- Publication date: July 1970
- Primary subjects: M104A1 and M104A2 Periscope Mounts
- Manual type: Direct-support, general-support, and depot-maintenance repair-parts and special-tools list
- M104A1 FSN: 1240-565-1091
- M104A1 later NSN: 1240-00-565-1091
- M104A1 part number: 8270627
- M104A2 FSN: 1240-777-6776
- M104A2 later NSN: 1240-00-777-6776
- M104A2 part number: 8270307
- Associated sight family: M28, M28C, and M28D periscopes
- Later catalog reference: NSN 1240-00-777-6776 may appear under the name Mount, Periscope, M10; Army drawing 8270307 identifies the M104A2
- Issuing authority: Headquarters, Department of the Army
- Country of origin: United States
- Item included: Technical manual only
How the Periscope Mounts Worked
The M104A1 and M104A2 were similar mounts designed to support an M28-series periscope inside an armored vehicle. A cylindrical rotary lock secured the sight when the operating handle was placed in the locked position. When unlocked, a spring-operated catch helped prevent the periscope from falling free. Military specifications required the mounts to operate during normal conditions and after exposure to temperatures ranging from approximately -40°F to 150°F.
Periscope and Weapon Applications
The associated M28-series periscopes were monocular optical sights used with cupola-mounted weapons and armored-vehicle fire-control equipment. These sights provided about 1.5-power magnification and a 48-degree field of view. A mechanical linkage allowed the line of sight to follow the weapon through a wide elevation range, while an M50 instrument light could illuminate the reticle for low-light use. M28-family sights were associated with vehicles including the M59 armored personnel carrier, M84 self-propelled mortar, M48 Patton tank series, M60 and M60A1 tanks, M67 flame tanks, and M132 mechanized flamethrowers. The exact mount and sight combination depended on the vehicle model and modification.
Historical Background
The M104 mount family was developed during the Cold War as the U.S. Army expanded its use of protected optical sights in armored vehicles. The related M28 periscope family supported several vehicle generations, from the M48 Patton of the 1950s to the M60 series that followed. These systems allowed crew members to aim a cupola weapon while remaining behind armor. M48A3 tanks and M132 mechanized flamethrowers were used during the Vietnam War, while M60-series tanks remained in American and allied service for many years. This July 1970 manual records the supply and maintenance system used to keep that specialized sighting equipment operational.
Condition
This is a military-surplus technical manual and may show cover wear, creases, stains, writing, faded printing, edge damage, or other signs of age and storage. Please check the pictures for the general condition of the item. This listing is for one TM 9-1240-317-35P manual only; the periscope mounts, sights, weapons, vehicles, and other equipment are not included.
Ideal For
This manual is well suited for collections and research projects covering U.S. Army optics, armored-vehicle fire-control equipment, and Cold War maintenance publications.
- U.S. Army technical-manual collections
- M104A1 and M104A2 periscope-mount research
- M28-series periscope parts identification
- M48 Patton and M60 restoration references
- Vietnam War armored-vehicle displays
- Military optics and fire-control collections
- Museum and archival collections
Approx length 8", Approx width 10", Approx height 1", 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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