Description
Technical Manual (TM 9-1240-309-35P) for XM44, XM44E1, and XM44E2 Tank Periscopes July 1970 FSN 1240-788-5463
U.S. Army Technical Manual TM 9-1240-309-35P for XM44-Series Tank Periscopes, July 1970, FSN 1240-788-5463
Item Overview
This U.S. Army technical manual is a repair-parts and special-tools reference for the XM44, XM44E1, and XM44E2 Tank Periscopes. Issued as TM 9-1240-309-35P in July 1970, it supported higher-level maintenance of these specialized fire-control instruments.
This listing is for the technical manual only. It does not include a periscope, image-intensifier tube, M551 Sheridan, mount, special tools, or other fire-control equipment.
About the XM44-Series Tank Periscopes
The XM44 series served as the gunner’s primary night fire-control periscope on the M551 Sheridan Armored Reconnaissance/Airborne Assault Vehicle. These sights combined a unity-power daylight channel with a passive low-light channel offering approximately 9-power magnification.
The passive system gathered available light and used an image-intensifier tube to improve nighttime visibility. A projected ballistic reticle placed an aiming pattern over the target image.
The periscopes consisted mainly of head and body assemblies containing optical, electrical, and mechanical components. Interchangeability depended on the model and assembly, making an illustrated parts manual especially useful when identifying replacement components.
Models Covered
This manual covers five related configurations:
- XM44: FSN 1240-788-5463
- XM44E1: FSN 1240-933-5630
- XM44E2: FSN 1240-176-1031
The “E” suffix identifies experimental modifications to the original XM44 design. These versions reflect continued efforts to improve the periscope’s construction, reliability, and serviceability.
M551 Sheridan Application
The M551 was a lightweight armored vehicle developed for reconnaissance, airborne operations, and mobile fire support. Its main weapon was the 152mm M81 gun/launcher, which could fire conventional ammunition and the MGM-51 Shillelagh guided missile.
The XM44-series periscope provided daylight observation and passive night aiming for conventional fire. Separate telescope and tracking equipment supported the guided-missile system.
Historical Background
The M551 entered U.S. Army service in 1967 and saw combat during the Vietnam War. Its advanced weapon, missile, and night-vision systems required detailed technical publications and a dependable supply of specialized replacement parts.
TM 9-1240-309-35P was published in July 1970, near the end of the Sheridan’s main production period. By then, several XM44 periscope variations had been developed. Listing all three models in one parts manual helped maintenance personnel identify differences and select the correct parts for each configuration.
The publication documents an important stage in the development of passive night vision. Unlike earlier active infrared systems, the XM44 used available light and did not require an infrared searchlight for normal low-light viewing.
Publication Details
- Manual number: TM 9-1240-309-35P
- Publication date: July 1970
- Subjects: XM44, XM44E1, and XM44E2 Tank Periscopes
- Manual type: Repair parts and special tools
- Maintenance levels: Direct support, general support, and depot
- Optical functions: Unity-power daylight viewing and 9-power passive low-light viewing
- Equipment role: Gunner’s night fire-control periscope
- Parent vehicle: M551 Sheridan
- Associated weapon: 152mm M81 Gun/Launcher
- Item included: Technical manual only
Collector and Research Value
This manual is a specialized addition to a U.S. Army technical-publication, armored-vehicle, night-vision, or military-optics collection. Its illustrated parts information can help museums, restorers, and researchers identify XM44-series assemblies and study changes between the five configurations.
Ideal For
- U.S. Army technical-manual collections
- M551 Sheridan research and displays
- XM44-series periscope parts identification
- Vietnam War armored-vehicle exhibits
- Early passive night-vision collections
- Military optics restoration references
- Museum and archival reference libraries
Approx length 8", Approx width 10", Approx height .75", Approx weight 1.5lbs.
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