1. Although this rule has a Keuffel and Esser cursor the rest of rule is not like any of my other KEs.
2. As its title suggests, the rule is for military use, principally use of trigonometry to calculate range.
3. The rule could be used to calculate easily the range of a target given the information in the diagram below. The values set up in the detailed view show:

• Use the cursor to set the "opposite angle" (55°) against the "base angle" (4.0°)
• Read the "range" (2350 yds) against the "base" length (200 yds).

4. In the diagram showing the above calculation you can see that the angles are marked both in degrees and mils; 90° equals 1600 mils. This unit, the mil, is actually quite convenient as, for a wide range of angles sin » tan » angle(in mils) /1000. For example 200 mils = 11.25 °; tan 11.25° = 0.199 and sin 11.25° = 195, both close to 200/1000. The agreement is closest for tan (240 mils)  as can be see in the lower diagram. One can see the advantage in a military situation; at a first approximation it is very easy to calculate and if you use the slide rule to get accurate values then it is easy to check the result. The diagram of the circle below, which gives appropriate formulae for different quadrants, uses mils rather than degrees which suggests that this was the preferred unit.

5. The upper part of the stock was screwed to the base of the stock.
6. The back of the rule had a range of trigonometrical formulae and diagrams.

Front view

Rear view

Detail showing ranging scales

Detail of formulae on reverse

Diagram showing measurements used