If your rifle is zeroed at 100 yards, anything closer or further will hit low. This is something we need to correct for. Using a .308 at 10 yards, my bullet will impact the target 1.6 inches low , at 200 yards, 4 inches low, and at 300, 14.5 inches low. Of course, this varies due to bullet speed. But for most real world applications, anything from 10 to about 250 yards, you can just aim and be "successful". Using an IPSC target and aiming at the top, you can still get hits out to 400 yards. But this isn't exactly longrange shooting and nowhere near precision shooting. We want to be precise. So, we need to know exactly how far a target is. There are a few ways to do this.
The first thing you need to understand is how your scope works. There are 3 types of scopes:
Fixed
First focal plane
Second focal plane
Fixed: With a fixed power scope, you can't adjust the magnification; however, your reticle will be true (1 mil = 1mil at any given distance). Typically, you can get a very good quality fixed scope at an affordable price.
First focal plane: With a first focal plane scope (ffp), you have the ability to adjust the magnification and the reticle is true at all powers. Your reticle will adjust size according to your magnification. First focal plane scopes are more common in longrange shooting. They are also typically more expensive. Be weary of inexpensive ffp scopes.
Second focal plane: With a second focal plane scope (sfp), you have the ability to adjust magnification, but your reticle is only true at a specific magnification. And each scope manufacturer will have a different power setting for the reticle to be true. This is probably the most common type of scope on the market. Sfp scopes can be extremely inexpensive.
If you're on a budget, I would recommend a fixed power scope. I do like very nice
($$$) scopes, but I use a fixed power on most of my rifles. If you have the money, get a first focal plane scope. I don't and won't own any second focal plane scopes. You can have just as much success with a spf scope but ffp and fixed is where it's at.
I will just leave it at that.
We can determine how far away a target is several different ways. We can look at it and estimate, use a laser rangefinder, maps, GPS, or our reticle. When I was learning longrange shooting, broke as hell, and before I knew you could use the reticle to measure distance, I literally cut a piece of string 50 yards long and walked the property to measure out to 500 yards. I was hard core dedicated and determined. Where there's a will there's a way.
The easiest way to determine distance is with a laser rangefinder. You can pick up an inexpensive rangefinder thats accurate out to a few hundred yards. But at a few hundred yards, you can be accurate enough with just your eyes. For 200 - 350 dollars, you can pick one up accurate to about 600 yards. Once you get to 1000 - mile, you're dropping a lot of coin. Most people don't have maps. GPS is a really good option, but we're going to focus on using our reticle. Remember, you can buy all the fancy gadgets, but when the batteries die, you have to be the weapon. Place your reticle on your target. How many mils tall or wide did you measure?
The formula I like to use (because I think in inches and yards) is:
Height of target (inches) x 27.77 ÷ Target size (mils) = Distance to target (yards)
Example: A target that is six inches wide, 8 in tall; Using our reticle if we measure across and get .5 mils
6 x 27.77 ÷ .5 = 333 yards
We would dial in our d.o.p.e to hit the target. In this example I would dial 1.6 mils. This is an accurate way to measure a target's distance out to about 600 yards. But there is a certain amount of error. With practice, you can measure easily .1 mil but anything less is almost impossible. Especially out to 1000 yards.
Example: a 10 inch target
10 x 27.77 ÷ .3 = 925 yards
10 x 27.77 ÷ .2 = 1,388 yards
We have a 463 yard error. If we look at our Danger Space, we have up to a 14 yard error on a 10 inch target. This means if our target is at 1,000 yards and we estimate it between 993 - 1,007 yards, we would be able to hit it. Anything outside of this danger space, we will miss.
Lets look at a 20 inch target:
20 x 27.77 ÷ .5 = 1,110 yards
20 x 27.77 ÷ .55 = 1,009 yards
Even with a larger target and less error on our measurement, we still have a 101 yard error. Well outside of our danger space. Definitely a miss. So what do we do?
Here is what I do.
First, by looking at the distance to the target, I estimate how far I think it is.
I then break down the distance into 100 yard increments using land marks to keep track and make a second estimate. Next, I use my reticle and measure the target. Lets say .5 mils on a 10 in target.
I run through the formula.
5 x 27.77 ÷ .5 = 555 yards
If there are other objects around of known sizes, I will mil those also. Using all the information I have gathered will give me the best chance to determine the correct distance. At this point, we have 2 options. Send it, or move closer.
Lets talk about some of the down side to milling a target. We know there can be an error when we get into the .1 or less mils. The other thing we have to know is our target size. This can make things more difficult. The best thing we can do (besides having a rangefinder) is have a log of common objects of know size.
Door - 36" x 80"
Window - 35" x 59"
ISPC Target - 29" x 18"
License plate - 12" x 6"
Vehicle inspection sticker - 4" x 2.5"
Deer - 36"
Pig - 24"
Elk - 57"
Fence (type) 72"
MIL SCOPES
Height of target (inches) x 27.77 ÷ Target size (mils) = Distance to target (yards)
Height of target (yards) x 1000 ÷ Target size (mils) = Distance to target (yards)
Height of target (inches) x 25.4 ÷ Target size (mils) = Distance to target (meters)
Height of target (meters) x 1000 ÷ Target size (mils) = Distance to target (meters)
MOA SCOPES
Height of target (inches) x 95.5 ÷ Target size (moa) = Distance to target (yards)
Height of target (inches) x 87.3 ÷ Tatget size (moa) = Distance to target (meters)
*TIPS*
Be aware of the angle of the target.
When milling a target, use a rear bag and get into the most stable position. Mil the target multiple times length and width.
📷
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