INTRODUCTION_

First off, shooting basically anything past 300 yards you are going to need to learn how to range your target. You can buy a cheap mil dot scope if you just want to practice. Depending on the location of the focal plane inside of the scope you may have to set it to a certain power for the "dots" to be calibrated to mils.

This is what you will be looking at.:




A 10 mils
B 5 mils
C 1 mil
D Scope Dependent
E 1 dot
F Scope Dependent




Before we get too far into this discussion you will need to understand MOA. MOA stands for Minute of Angle. MOA is technically 1/60th of 1 degree (hence the term). This roughly comes out to 1" at 100 yards. There is a HUGE misconception out there that people think MOA "just means an inch." For example if you shoot a 1 inch group at 25 yards you have just shot a 4 MOA group. If you shoot a 2 inch group at 200 yards you have just shot a 1 MOA group.
. More MOA examples:

• 3 inches at 300 yards is 1 moa
• 1 inch at 50 yards is 2 moa
• 6 inches at 200 yards is 3 moa
  

Another big key word here will be mils. Before you can use "mils", you need to understand what they are. Similar to MOA, a mil is the angle of 1 meter at 1000 meters (or really, 1 unit wide per 1000 units of length). With a little bit of math you can range any target with a known size.

Another quick note before we begin: some of these formulas produce meters, and some are designed to use yards. Keep track of your units of measurement and don't get them crossed up. There are 110 yards per 100 meters if I recall correctly.

RANGE YOUR TARGET_

Size of object in METERS X 1000
-------------------------------------------- = distance in METERS
Size of object in mil dots

OR

Size of object in YARDS X 1000
-------------------------------------------- = distance in YARDS
Size of object in mil dots

OR

Height of item in inches x 27.8 (25.4)/Mils read = Distance to target in yards (meters)

Now, how tall is a "zombie"? Most likely pretty darn close to 6 feet (2 yards) so we will use that for conversion's sake. So, for a human-ish target you can basically take the number 2000 and divide it by how ever many mils the target is as seen through the scope. So, if your zombie takes up 5 mils in the scope then we know that it is 400 yards away.






COMPENSATE FOR DROP_
You will need to find a drop table for the exact cartridge you are using. I think Winchester does drop tables for their factory ammo, but there are sites on the internet that will let you put in custom ammo data IF you have it already.
(There is a link to one of the best ballistics calculators / range card generators at the bottom of this page)

Here is a sample drop table for 62 grain .223 @ 3000 fps zeroed at 100 yards. (10mph wind also introduced)

Range	Drop	Drop	Windage	Windage
Yards	Inches	MOA	Inches	MOA
0	1.5		0
100	0	0	1.1	1.0
200	3.4	1.6	4.6	2.2
300	13.2	4.2	11.0	3.5
400	31.2	7.4	20.8	5.0
500	60.1	11.5	34.9	6.7
600	103.5	16.5	54.0	8.6
700	166.4	22.7	78.6	10.7
800	254.4	30.4	108.5	12.9

COMPENSATE FOR WINDAGE_
Now we have a good range. The next thing you are going to need is to calculate your windage. There are formula's for that, but honestly unless you really know what you are doing it is best to stick with a wind table such as I have listed above in conjunction with the drop table. Notice that I have the wind set to 10mph. If the wind were actually only 5mph when I went out to shoot, then I could just chop those adjustments in half. Also, if the wind is not blowing directly to your left or right, you will need to make further adjustments such as the picture below describes.

If you are dead set of calculating windage by using a formula then here you go:

RANGE(IN HUNDREDS OF YARDS) X WINDSPEED(IN MILES PER HOUR)
-------------------------------------------------------------------------------------------------------- = MOA ADJUSTMENT
CONSTANT

Example list of constants: (THESE NUMBERS WILL VARY WITH CALIBER AND VELOCITY)
(EXPERIMENT WITH YOUR OWN CONSTANT NUMBERS)
1-500 yards C=15
500-600 yards C=14
600-800 yards C=13
800-900 yards C=12
900-1000 yards C=11

YOU CAN FIND OUT YOUR CONSTANT NUMBERS BY USING THE WINDAGE CHART AND WORK IT BACKWARDS WITH KNOWN RANGE, WINDSPEED, AND MOA ADJUSTMENT TO MAKE YOUR OWN CONSTANT CHART
EXAMPLE:
YOU KNOW FROM THE DROP CHART ABOVE THAT MY MYSTERY CALIBER ABOVE AT 600 YARDS WITH 10MPH WIND IS 8.6 MOA DRIFT. SO:
(6 X 10)
----------------- = 8.6 Which when simplified: 60 / 8.6 = constant number for 600 yards
CONSTANT


So our constant would be approximately 7 for the caliber listed in the DROP chart at 600 yards



I still prefer to use the windage table in conjunction with the drop table. It takes a lot of the guess work out of the equation. The fewer equations you have to use, the less chance you have of botching your shot.




Most scopes use 1/4 MOA clicks. Some scopes use 1/10th mil clicks, but for this discussion we are going to assume a scope with 1/4 MOA clicks. Let's say for this particular engagement we are going to shoot a target at 600 meters, with 10mph wind blowing at a 45 degree angle to our position.

See if you can figure out the adjustments before reading further.

-----------------------------------------------------





PUTTING IT ALL TOGETHER_
600 meter target, wind at 10mph half value (due to direction).

What does our table say for drop? 16.5 MOA adjustment. So, multiply that by 4 (because our scope is using 1/4 moa clicks). We will need to give our scope 66 clicks up. What does our windage table say? 8.6 MOA for 10mph wind, however since the wind is blowing at a 45 degree angle we will cut that in half. So, 4.3 MOA of adjustment. Multiply that by 4 and we get 17 clicks. Now give the scope 17 clicks into the direction of the wind.

You must also ensure that your scope parallax is set correctly. This will ensure that the position of your eye as it looks through the scope isn't going to affect the point of aim. Some cheaper scopes have the parallax set at 100 yards and cannot be changed. Some scopes have an adjustment on the front lens, and some have a sidewheel parallax adjuster on the opposite side of the windage adjustment. If this is not set properly, you will likely miss your shot that you have spent all of this time figuring calculations on. Some scopes will have a "number" etched in to use to dial in the parallax adjustment, and some will not be marked and must be set by aiming at the target and moving your eye around to see if your point of aim changes.

Now you have your parallax, drop, and windage set on your scope. Next you need to determine if you are level with your target. If the target is at a higher or lower elevation you will have to aim LOWER either way.

Despite common belief, if the target is higher than you you will aim lower. If the target is lower than you, then you will still aim lower than your target. Aim LOWER either way! The amount of hold for elevation differences will come with practice, and I do not know of any formulas to calculate it. For most instances you can aim for the pelvis to compensate just in case. Any time that gravity is not pulling straight down on the bullet as it flies through the air, it will cause it to shoot higher than normal. This is true if shooting while angled up or down.

GENERAL NOTES_
Now the rest is basically on you and your equipment and how well you zeroed your rifle. If you have a junk scope that the clicks aren't exactly 1/4 moa, or don't return to zero properly then you don't have much chance. A good zero is very important.

The higher that your scope is off of the bore, the more important it will be to keep the rifle perfectly level. When you introduce cant into a long range shot it can really throw things off.

Keep in mind that if it is colder outside than when you zeroed the air will be more dense which will slow down the bullet causing it to hit lower than normal.

Also, elevation change also will shift your POI for the same reasons as temperature change. You will need different drop charts for shooting in different temperatures and altitudes.

When making long range shots you will also notice mirages. A mirage will distort your view of the target, and you will need to learn how to read them. You can determine wind speed by reading the mirage. There is more information on this subject listed in a link below.

Making large scope adjustments like described above are best done with a scope that has resettable turrets. Some scope turret caps like on the Leupold Mark 4 have the range built into the top turret, so once you range your target you can just set the scope to 600 yards or whatever and not have to count clicks.

LINKS_
If you feel comfortable with the information listed above, head to the site listed below. It is a long range shooting simulator that is perfectly accurate and free to use.
http://shooterready.com/moademo.html

Army FM 23-10 (Field Manual for Long Range Engagements)
FM 23-10

I recommend JBM for range cards:
JBM Ballistics Calculator

1000 yard calibration targets for use at 100 yards can be found at the bottom of this page:
CATS calibration targets

Here is a useful guide on how to read the wind (if you do not know the wind speed)
How to Read the Wind

This is a useful guide for making windage adjustments if you do not have the data on your drop chart (also discusses the effects of visual distortion due to heat):
Windage Formula

This page was written by Possumblaster

Further helpful information will be posted below this line. This will be information from other websites that I have deemed useful.

ANYTHING BELOW THIS LINE I DID NOT WRITE PERSONALLY.

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FURTHER NOTES ON MOA:
COPY/PASTA FROM MIL-DOT.COM
Minute-Of-Angle The term "minute-of-angle" (MOA) is used regularly by target shooters at the range, but is probably understood thoroughly by few (the same goes for mil-dots). Defined loosely, one MOA = 1" @ 100 yards; so, if you shot your rifle 5 times into a 100-yard target and every shot went into a one-inch circle you had drawn on the paper, then your rifle could be said to shoot 1 MOA. Likewise, if every shot goes into a two-inch circle at 200 yards, then you're shooting 1 MOA. A 10-inch group at 500 yards would be 2 MOA. Now for the fun part. There are 360 degrees in a circle. Each degree can be broken down further into minutes. There are 60 minutes in a degree. Likewise, there are 60 seconds in a minute. Now, to figure out the distance subtended by 1 minute at any particular distance, we need merely to plug those two values into a simple trigonometric equation. The tangent function fits the bill nicely. Here's the equation: tan(angle) = distance subtended/distance to the target
(units must be consistent--e.g., 1/36 of a yard [1"] divided by 100 yards) Now, we know the angle (1 minute or 1/60 of a degree) and we know the distance to the target (100 yards), but we need to figure out the actual distance subtended at the target (i.e., is 1 MOA actually 1" @ 100 yards?). What we need to do is solve for "distance subtended." Here's our final equation: tan(angle)*distance to the target = distance subtended Make sure your calculator is in "degree" mode (as opposed to "radian" or "gradian") and type in 1/60 (for degrees) and hit the "tangent" button. Then multiply that by 100 yards. This should give you the distance (in yards) subtended at 100 yards. Multiply this by 36 to get inches. The answer should be: 1.047197580733" This is just a hair over the commonly quoted "one inch." At 1000 yards, this would be almost 10 1/2 inches. Apparently, it is just a coincidence that 1 MOA happens to be REALLY close to 1" @ 100 yards. It is, however, quite convenient.

HOW TO COMPENSATE FOR MOVING TARGETS(AGAIN FROM MIL-DOT.COM)
Leads for Moving Targets When a shooter is training on moving targets he should be taught to calculate leads for moving targets knowing the targets speed, time of flight of the bullet and the targets direction of movement. The formula is: Time of flight (sec) x Speed of target (fps) = Lead from center-mass in feet
(full value lead) Since it is easiest to establish a lead from a target's leading edge and we want a lead in mils we will then use the formula: (Lead in feet x 12) ? 6
(Range x .01) x 3.4 We can now use our mil dot reticle to hold off instead of having to guess at target widths and other not-so accurate methods. This formula is a bit ungainly to use in tactical situations, and it doesn't take into account different shooters' reaction times, but it should be used in training to determine starting leads when engaging live fire moving targets. The shooter then fine tunes his leads and writes them in his data book.