Table Two contains basic velocity and energy data.
| ENERGY | 2520 | 2180 | 1870 | 1600 | 1355 | 1150 | 970 | 815 | 690 | 590 | 510 |
Normally it's much better to wait and engage your target when he pauses momentarily rather than attempt a moving target shot. But a moving target may be the only shot you've got.
All the data published in Table Three reflects a target moving 90 degrees to the path of your bullet, that is, moving directly right or left, which is FULL VALUE. Should the target move oblique right or left, whether toward or away from you, use ONE HALF the value since in relative terms he's crossing your front at half the speed. And when he's heading directly toward you or away from you, there's NO VALUE and no movement compensation or leads at all. Aim dead-on.
Must you actually carry all this data in your head? No. I memorize just the 3 MPH leads, then double them for a trotting target and triple them if it's at a dead run. And I can mentally cut in half any one of these if the target's moving obliquely.
The easiest way to remember the 3 MPH moving target leads is to COUNT IN SEVENS -- 7, 14, 21, 28, 35, 42 and you'll have the correct walking leads almost perfectly for 100, 200, 300, 400, 500 and even 600 yards.
The best reaction to a stiff crosswind is to shift your location so you're either perfectly upwind or downwind from your target and thereby eliminate the effect of wind altogether.
When relocating is physically or tactically unfeasible, the Wind Data in Table Four allows great accuracy when properly applied.
And don't forget that unlike a moving target, an oblique wind is NOT 1/2 value but 3/4 value since a bullet is very sensitive to a crosswind.
While the book explains this phenomenon in depth, just let it be said here that up/down shooting requires aiming LOW for compensation. Despite it not seeming logical, this is equally true whether your target is downhill or uphill; always compensate by
Keep in mind how quickly angles increase as a suspect's position gets higher above street-level -- by the time he's about 4 - 5 stories or higher, and youre across an average downtown street, he's probably already 40 degrees UP. The Austin 'Texas Tower' gunman, Charles Whitman, fired from a 28-story perch about 50 degrees UP from most-lawmen, who typically returned fire from cover 300 yards away. This means their uncompensated shots probably hit about ten inches high and helps explain why it took so long to neutralize him.
We computed this data for UP/Down angles at 5 through 60 degrees in Table Five, just so you could get a better feel for the effect. (Sixty degrees is the angle at which the greatest compensation is required.)
To keep from dazzling you with too much complicated up/down information, I've included "Simplified UP/DOWN Data' (Table Six) which shows the compensation needed at 100 yards for 30-, 45- and 60-degree up/down targets. You can see that theres little com¬ pensation required at such short range until the angle approaches 60 degrees, and even then you need only aim 1.3 inches LOW to be perfectly on-target.
So that you can see how to translate this up/down data into 1/4 Minute of Angle scope adjustments, we've included Table Seven, which shows these computations for a 45 Degree Slope.
The idea of Comeups is to KNOW the exact Minutes of Angle a rifleman needs to raise his sights in order to hit dead-on, when changing from one distance to another, at 100-yard intervals.
A scope-equipped police rifleman uses Comeups either with target knobs or even just an elevation ring, to count off 1/4 MOA clicks as he cranks to another elevation. Comeups are calculated for a specific round -- based on bullet weight, velocity and resulting trajectory. The ones listed in this table exactly fit the Federal .308 Match trajectory and would not apply perfectly even to the very similar 7.62mm military Match bullet.
Most modern, quality riflescopes adjust elevation with 1/4 Minute of Angle clicks, which means you must click-off four increments to equal one Minute of Angle. If you have any doubt about your scopes elevation increments, check with an armorer or the manufacturer.
Also understand that the Comeups shown in Table Eight work REGARDLESS of your zero range. In essence, they tell you how much to go up or down from one zero so you'll be zeroed at the next range. There may be tiny variations between these calculations and your own rifle's performance, so testfire and modify them for the most precise results.
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