| 摘要 |
The invention relates to a targeting device comprising a casing which houses a wheel. The wheel is weighted and free to rotate relative to the casing. A mount on the casing mates with a receiving apparatus on the rifle, thereby securing the casing to the rifle. The wheel's absolute orientation remains fixed, while the casing rotates with the rifle as it is aimed upward or downward. The casing has a window through which the wheel is visible. For any angle at which the rifle is positioned, a marker inscribed on the wheel aligns with a cosine number inscribed on the window, indicating the cosine of the angle at which the rifle is positioned. The cosine numbers are readable without requiring the shooter to break his cheek weld with the rifle. The shooter can then calculate the horizontal distance to target by multiplying the cosine by the straight-line distance to target.
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