Competitors used data books to track zeroes, plot hits and record scores. The books also contained windage diagrams for M72 .30 cal. and M118 7.62 cal. USGI match ammo.
Windage diagrams were a great asset in competition. epending on range estimating skill they can be useful in the field.
Below is a link to an Adobe pdf file of the USMC Competitive Rifleman's Data Book (3951)
It contains Windage Diagrams for 200, 300, 600 & 1000 yards. The diagrams were created for competition on known distance ranges.
--The diagrams consist of a series of concentric circles.
--Each circle represents a wind velocity.
--The radial "spokes at 12 oclock & 6 oclock show the wind velocity for that circle.
--The roman numerals around the perimeter are the clock position for wind direction.
--To use the diagram: (A) determine range. (B) estimate wind direction & velocity. (C) pick out the velocity circle. (D) follow the circle to the roman numeral wind direction. (E) read the windage correction. (F) put the correction on the sight.
Example: From the 300 yd diagram assuming a 9 oclock (IX) 15 MPH wind shows (4) 1/2 MOA CLICKS = (2) MOA of windage adjustment required.
NOTE: These diagrams are for NM rear sights with 1/2 MOA clicks. For a standard 1 MOA per click rear sight reduce by half.
The book also contains: (A) target diagrams with size info, (B) plotting sheets, (C) weapon data form.
The only thing it lacks is info on how to estimate wind speed.
I recommend that anyone interested in this download and save it - it could disappear at any time. It is a pdf file and can be printed out.