Inclined Fire, part #3: Options
Wed, 21/05/2014 - 21:28
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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