Firefield FF12003, User Manual

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USING THE RANGEFINDING RETICLE
The Firefield Siege 10x50R Tactical Monocular uses a mil reticle. Mil stands for millra-
dian. A millradian is 1/6283.2th of a circle, or 3.438 MOA. The millradian represents
1 unit at 1000 yards. To simplify, a target that is one yard tall at 1000 yards would
measure 1 millradian. Each hashmark in the 10x50’s reticle is 5 mils.
Calulation Method
In order to determine distance there are three variables: target size, mils read, and range. In order to determine distance, the tar-
get size must be known. By using the reticle to measure target height the following calculation can be used to derive an estimated
distance.
Target size (in yards) x 1000 / Mils read = yards to target
For example, a full size deer is approximately six feet long. Convert feet into yards (3’ = 1yd), so the deer is 2 yards long. Now
measure the deer with the mil reticle; it is 10 mils long. Next, mulitply the target size (2 yards) by the constant of 1000. This
equals 2000. Now divide 2000 by mils read (10), this equals 200. So the deer is roughly 200 yards away.
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