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How to read a Vernier Sight

    A vernier sight staff scale is usually inscribed with graduations marks that are placed at intervals of 20 to the inch. (0.050")

    The moveable portion of the sight or "slider" or "eyepiece" will be inscribed with 5 and sometimes 6 lines. These lines are numbered from 0 to 4 or 5 and inscribed at intervals of 25 to the inch. (0.040")

             

    Each of the marked intervals on the staff may be sub-divided into five additional graduations or "Points" by sequentially aligning the inscribed lines on the slider with a scribe mark on the staff.

    This allows precise adjustments of the eyepiece to be made in increments of 1/100th of an inch. (0.010")

    Each of these 1/100th of an inch adjustment increments may be referred to as a "Point".

    Each inscribed graduation mark on the staff represents 5 points.
    (1/20" = 5 points, 3/20" = 15 points, 1/4" = 25 points, 1/2" = 50 points, 3/4" = 75 points, 1" = 100 points, etc.)

    Setting and reading the scale in points:
1. Move the eyepiece slider until the #0 scribe line is aligned with the mark labeled 1/4 on the staff for a setting of 25 points. (Note that #0 is the only line on the slider that is aligned with a mark on the staff - If the slider contains 5 lines, the #5 line is also aligned with a mark)
2. Move the eyepiece slider up until the #1 scribe line aligns with a mark on the staff for a setting of 26 points. (Note that the #1 line is now the only line on the slider that is aligned with a mark on the staff)
3. Move the eyepiece slider up until the #2 scribe line is now the only line aligned with a mark on the staff for a setting of 27 points.
4. Move the eyepiece slider up until the #3 scribe line is now the only line aligned with a mark on the staff for a setting of 28 points.
5. Move the eyepiece slider up until the #4 scribe line is now the only line aligned with a mark on the staff for a setting of 29 points.
6. Move the eyepiece slider up until the #0 scribe line is again aligned with a mark on the staff for a setting of 30 points.
7. Continue to move the eyepiece slider up until the #1 scribe line is again aligned with the next mark on the staff for a setting of 31 points, etc., etc.
8. To read a setting, first determine the staff mark number that is below the #0 line on the slider and then add the number of the slider line that is aligned with a mark on the staff for the point reading.
(25 + 2 = 27 points, etc.)
9. If the #0 line is aligned with a mark on the staff, then the staff mark number is the point reading.
( 25 points, 30 points, 35 points, etc.)
10.

If the rifle has a sight radius of 36 inches, a sight adjustment of one point will cause the bullet impact to be moved 1 inch at 100 yards, 2 inches at 200 yards, 10 inches at 1,000 yards, etc.

If the rifle has a sight radius of 34.4 inches, a sight adjustment of one point will cause the bullet impact to be moved 1minute of angle or 1.047 inches at 100 yards, 2.094 in at 200 yards, 10.47 inches at 1,000 yards, etc.

 

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This page updated on 8/27/2012