Description
U.S. Army Technical Manual Change 1 to TM 9-1290-322-35 for M15/T23E2 Elevation Fire Control Quadrant, January 1971
Item Overview
This U.S. Army publication is Change 1 to TM 9-1290-322-35, the maintenance manual for the M15 Elevation Fire Control Quadrant, formerly designated T23E2. Issued in January 1971, this change updated the original manual dated December 20, 1962. It covers the quadrant identified by FSN 1290-896-2236. This listing is for the Change 1 update only. It does not include the complete base manual, the separate TM 9-1290-322-35P parts manual, an M15 quadrant, a weapon, or other equipment.
Publication Details
This change was prepared for trained Army personnel responsible for maintaining mechanical artillery fire-control equipment.
- Publication: Change 1
- Manual number: TM 9-1290-322-35
- Change date: January 1971
- Original manual date: December 20, 1962
- Subject: M15/T23E2 Elevation Fire Control Quadrant
- Federal Stock Number: 1290-896-2236
- Later National Stock Number: 1290-00-896-2236
- Manual level: Direct support, general support, and depot maintenance
- Issuing authority: Headquarters, Department of the Army
- Country of origin: United States
- Item included: Change 1 update only
About Change 1
Army change publications kept technical manuals current after their first issue. They supplied filing instructions and revised material for selected parts of the base manual. Change 1 should be kept with the December 1962 edition of TM 9-1290-322-35 to create a more complete maintenance reference. Because this is an update rather than a full manual, it may not be useful by itself for every repair task.
About the M15/T23E2 Quadrant
The M15 is a mechanical fire-control instrument used to measure and set a weapon’s elevation in mils. T23E2 was its development designation before standardization as the M15. The unit includes elevation and correction counters, level vials, and controls for leveling and cross-level adjustment. Its cross-level system helps correct for vehicle or carriage cant when the weapon is standing on uneven ground. These features helped artillery crews lay the gun at the elevation ordered by the fire-direction center.
Documented Weapon Applications
The M15 served as part of the sighting equipment on several tracked artillery systems introduced during the early 1960s.
- M108 105mm self-propelled howitzer
- M109-series 155mm self-propelled howitzer
- M107 175mm self-propelled gun
- M110-series 8-inch self-propelled howitzer
Weapon-System History
The M108 and M109 were related turreted artillery vehicles built for mobile fire support. The 105mm M108 had a shorter U.S. service life, while the 155mm M109 became one of the Army’s longest-serving self-propelled howitzer families. The open-topped M107 and M110 shared another tracked chassis. The M107 carried a long-range 175mm gun, while the M110 used an 8-inch howitzer for heavy shell fire. All four systems relied on accurate sighting instruments to turn fire-direction data into the correct gun position.
History of Use
The original manual appeared as these Cold War artillery systems entered service. Change 1 was issued in 1971, during the Vietnam War and a period of heavy use for American self-propelled artillery. In the field, crews used the M15 to set elevation for indirect-fire missions and to check the weapon’s position before firing. Maintenance personnel kept its counters, controls, level vials, and internal mechanisms accurate. The M15 remained associated with later versions of the M109 and M110, giving this update value as a record of a long-serving artillery fire-control instrument.
Collector and Research Value
This Change 1 publication is a specialized addition to a U.S. Army manual, Vietnam War, artillery, or fire-control collection. It is useful for studying how the Army updated maintenance instructions while equipment remained in service. It may also help museums and restorers document the M15 quadrant and the sighting systems used on early self-propelled artillery.
Condition
This vintage military technical-manual change may show cover wear, edge wear, folds, yellowing, stains, writing, stamps, punched holes, loose pages, or other signs of age and storage. Printing details and condition may vary between available copies. Please check the pictures for the general condition of the item.
Ideal For
This publication is well suited for collections, restoration research, and displays covering Cold War and Vietnam-era artillery.
- U.S. Army technical-manual collections
- M15 and T23E2 quadrant research
- M108 and M109 howitzer displays
- M107 and M110 artillery research
- Vietnam War military collections
- Museum and archival reference collections
Approx length 8", Approx width 10", Approx height .15", 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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