Description
U.S. Army Technical Manual TM 9-1290-333-15 for M2 Unmounted Magnetic Compass, November 1963
Item Overview
This U.S. Army technical manual covers the operation and maintenance of the M2 Unmounted Magnetic Compass, FSN 1290-930-4260. Issued on November 7, 1963, it provided military personnel with one reference for operating, inspecting, caring for, and maintaining this portable fire-control instrument. This listing is for the technical manual only. It does not include an M2 compass, M19 carrying case, weapon, or other equipment.
Publication Details
The full title is Operator, Organizational, Field and Depot Maintenance Manual: Compass, Magnetic, Unmounted: M2. The “15” suffix reflects its broad coverage from operator care through higher maintenance levels.
- Manual number: TM 9-1290-333-15
- Publication date: November 7, 1963
- Subject: M2 Unmounted Magnetic Compass
- Federal Stock Number: 1290-930-4260
- Manual type: Operator, organizational, field, and depot maintenance
- Issuing authority: Headquarters, Department of the Army
- Country of origin: United States
- Associated equipment: M19 leather carrying case
- Item included: Technical manual only
Manual Coverage
TM 9-1290-333-15 explains the compass’s construction, controls, characteristics, and operation. It covers magnetic azimuths, grid azimuths, angle-of-site readings, declination adjustment, inspection, preventive maintenance, troubleshooting, shipment, and limited storage. The manual also includes instructions for care under unusual weather, dusty, or sandy conditions, along with basic issue items and a maintenance-allocation chart.
About the M2 Magnetic Compass
The M2 is a compact, multipurpose instrument used to obtain clinometer, angle-of-site, and azimuth readings. Its features include front and rear folding sights, a sighting mirror, circular and tubular levels, an adjustable azimuth scale, and a protected magnetic needle mounted on a jewel bearing. The body was made from nonmagnetic material except for the needle and its pivot. Closing the compass automatically lifted the needle from its pivot to help protect the sensitive bearing.
M2 Compass Characteristics
The M2 was designed to provide more precise readings than a basic marching compass while remaining small enough for field use.
- Azimuth scale: 0 to 6,400 mils
- Angle-of-site scale: Minus 1,200 to plus 1,200 mils
- Dimensions when closed: Approximately 2-3/4" by 1-1/8"
- Compass weight: Approximately 8 ounces
- Primary readings: Magnetic azimuth, grid azimuth, clinometer, and angle of site
- Sighting equipment: Folding front and rear sights with mirror
- Original carrying equipment: M19 leather carrying case
Fire-Control Equipment History
The M2 compass entered military use during World War II and followed the earlier M1 compass. One important improvement was its scale graduated in mils, which matched the angular system used for artillery and mortar fire control. This allowed soldiers to work directly with fire-control measurements without first converting degrees into mils. The design remained useful through the Cold War and continued to appear in later Army manuals.
Weapon-System Applications
The M2 compass supported many indirect-fire weapons rather than one specific gun or mortar. Field artillery and mortar personnel used it during reconnaissance, weapon emplacement, survey work, and fire-direction tasks. It helped establish a direction of fire, orient gun and mortar positions, measure vertical angles, and confirm that weapons along a firing line were pointed on the ordered azimuth. Engineers and survey personnel could also use the compass for field measurements.
History of Use
In the field, the M2 could measure magnetic azimuths or provide grid azimuths after its scale was adjusted for local magnetic declination. Its angle-of-site mechanism allowed personnel to measure the vertical angle between the compass position and a target or reference point. The instrument also served as a portable backup when a larger aiming circle or surveying instrument was unavailable. Its small size, protective carrying case, and multiple functions made it useful during combat operations, training, and position preparation.
Historical Background
This November 1963 manual was published while the U.S. Army was modernizing its artillery, mortar, and surveying equipment during the Cold War. The manual identifies itself as a first edition issued before completion of the full technical review. This detail makes it an interesting record of how the Army documented and supported an established World War II-era fire-control instrument during the early 1960s.
Collector and Research Value
TM 9-1290-333-15 is a useful reference for identifying, operating, displaying, or restoring an M2 compass and its M19 carrying case. It also documents the practical field methods used to orient artillery and mortar positions before electronic navigation equipment became common. The manual is a specialized addition to a military-compass, field-artillery, mortar, surveying, or Army technical-publication collection.
Condition
This vintage military technical manual 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 manual is well suited for collections, research projects, restoration work, and historical displays covering military navigation and indirect-fire equipment.
- U.S. Army technical-manual collections
- M2 military-compass owners and collectors
- Field-artillery and mortar research
- Military surveying and navigation displays
- M19 carrying-case identification
- World War II and Cold War 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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