The M2 military compass has been in use for over a century and in service with the U.S. military since at least World War II. It is designed for precise work in providing targeting information for artillery. Due to this precision, it has also found use in civilian and recreational land navigation. Brunton markets a civilian version known as the Bruntion ComPro Pocket Transit, which is available in a number of models.
Open the case and extend the rear sight holder level with the compass. Raise the rear sight at the end of the rear sight holder until it is perpendicular with the compass face.
Fold the front sight at the end of the mirror until it is parallel with the mirror, then fold the mirror until it is at an approximately 45 degree angle with the compass face.
Ensure that the sights are aligned properly by seeing if the compass needle’s black end can be viewed when looking through the rear sight.
Brace your arms against your body and hold the compass level while looking through the rear sight.
Align the target object through the window in the mirror and align the hairline on the mirror with the reflection of the compass face.
While ensuring the bubble is at the center of the circular level and the object, hairline and reflected compass face are still aligned, read the azimuth at the black end of the compass needle. Measurements can be determined in degrees or mills, depending on the level of accuracy needed.
Because the M2 military compass uses a magnetic needle, iron objects, magnetic sources and power lines can trigger false readings.