Inclined Fire, part #3: Options

Now let's see when inclination does matter.

The table below shows what happens when slope is ignored, i.e. there is no correction for inclination. (Errors in cm, same color coding as above).

GP11 vertical miss distance, cm


10 15 20 25 30
300 1.2 2.9 5.2 8.5 12.8
350 1.7 3.9 7.3 11.9 17.9
400 2.3 5.4 9.9 16.0 24.0
450 2.9 6.9 12.8 20.7 31.2
500 3.8 8.7 16.1 26.2 39.4
550 4.6 10.8 19.9 32.4 48.8
600 5.6 13.1 24.4 39.6 59.8
650 6.7 15.8 29.4 47.9 72.2
700 7.9 18.8 35.0 57.0 86.0
750 9.3 22.3 41.3 67.4 101.7
800 10.9 26.0 48.3 79.0 119.3
850 12.6 30.2 56.3 91.9 139.0
900 14.5 34.9 65.0 106.4 161.0
950 16.6 40.0 74.7 122.5 185.3
1000 18.8 45.7 85.6 140.2 212.5







-10 -15 -20 -25 -30
300 1.3 3.0 5.4 8.8 13.0
350 1.8 4.2 7.7 12.2 18.4
400 2.5 5.8 10.4 16.7 24.7
450 3.4 7.6 13.5 21.6 32.2
500 4.3 9.6 17.2 27.6 41.0
550 5.4 12.0 21.5 34.3 51.2
600 6.6 14.7 26.5 42.3 62.8
650 8.1 17.9 32.1 51.2 76.1
700 9.7 21.5 38.5 61.3 91.2
750 11.7 25.7 45.9 72.9 108.3
800 13.7 30.3 54.1 86.0 127.6
850 16.1 35.5 63.3 100.6 149.2
900 18.9 41.4 73.6 117.1 173.4
950 21.9 47.9 85.2 135.4 200.6
1000 25.4 55.4 98.3 156.0 231.1

Middle distances look abysmal for all but very mild inclination angles and appear to require ballistic calculator, precomputed tables, or at least some heuristic better than "aim low".

There are several such heuristics. The three most popular are Rifleman's rule, improved rifleman's rule, and Sierra's:
http://www.exteriorballistics.com/ebexplained/article1.html

The fourth method is taught by NDS, and fifth is described later in this series.

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