Sniping Unplugged: Cracking the Code With 5th Grade Math
Because Murphy’s law never takes a day off, SWAT operators always need at the least, one backup option. You have flip up sights on your entry rifle because you have experienced the electronically generated dot of your choice fail without warning. I am betting that you will also have a sidearm secured to your plate carrier or holstered on your thigh along with a knife, strategically positioned for quick access if needed. Sniper missions require the same amount of redundancy. Calculators require light and/or batteries to operate. Slide rules can’t be read in darkness. Laser range finders sometimes fail like the red dot mounted on your match grade upper, not to mention their environmental limitations. Night vision (even the inexpensive units) can betray your location if your laser range finder is used in darkness. Every paranoid meth cook and wannabe terrorist can afford it. Suppose you had to navigate through water to get to your vantage point, will any of your battery-powered gizmos still perform, provided you even have them with you? Dead batteries will be a weak excuse to explain mission failure during a hot wash. If you do not have a plan for ranging in a situation that requires you to be totally blacked out, and your DOPE cards or slide rule are not in Braille, then you are left hoping that you never have to respond to such a scenario.
When we practice with the common formulas that are required to range objects with our optics, we do so with calculators or smart phones and pat ourselves on the back when we get the correct answers simply because we put in accurate data. You are setting yourself up for failure if you don’t have a plan that doesn’t include your downloaded shooter’s app. It takes some practice, but you can learn to operate battery-free by mentally breaking down the common formulas for range estimation. There are two commonly used Milradian ranging formulas. Most mil scope shooters choose one over the other, but each gives reliable answers.
Size of object in yards x 1000 divided by size of object in mils. Rule of 4s Method
Getting through the first part of the equation requires dividing the size of the object in inches by 36 to determine size in yards. Dividing anything by 36 on the fly is a bit intimidating. It would be simpler if we lived in a metric system friendly part of the world where we could easily convert centimeters to meters. It takes very little effort to convert 37 centimeters into .37 meters. But we don’t live there and I am willing to bet that a 20-inch wheel and a 36-inch-wide residential door will still be marketed as such for another generation or so. So, we must work with what we are presented. To avoid taking the troublesome 36 denominator head on, we can use simple multiplication and addition, using what I call the Rule of 4s Method. There are 36 inches in every yard, which unfortunately doesn’t correspond with the number of digits on our hands. That rules out the possibility of multiplying/dividing by 10 to get a metric system type of shortcut. But, most within our ranks are able to count in increments of 4, so let’s start there. 36 inches when divided by 4 equals 9. Therefore, every 4 inches represents 1/9th of a yard. 1/9th of anything is 11.1 percent.
Size of object in inches x 27.77 divided by size of object in mils, Money Method
For both formulas, an object larger than 36 inches will require an extra digit in the size of object in yards and size of object in inches x 27.77 portion of the equations. Using 40 inches in the Rule of 4s formula, assign a value of 1 to the first 36 inches and .111 for the remaining 4 inches to get 1.111 total. After moving the decimal point 3 places to the right, the size in yards x 1000 measures 1111. Using the Money Method, 40 inches represents $10.00 (1000 cents). Then add 100 cents , then 10 cents and total for 1110 cents (1110).
All that remains now to determine the distance is to solve the size of object in mils portion of either formula which is fortunately much easier. I offer my preferred method as an example.
We learn on day one of Basic SWAT training that the maximum range of an excuse is 0 meters. Failing to prepare is often the culprit when things do not go well. Not having a have a solid backup plan for a worst-case scenario in a tactical environment is a recipe for failure and also represents a big, fat, slow moving target for civil attorneys. If ranging calculations are incorrect, any subsequent wind or slope adjustments will be incorrect also. Devote and document some of your structured training time to develop your team’s skills. Realistic training is necessary to master your craft, and mastery is the standard required and expected, with or without batteries
[B1]
Because Murphy’s law never takes a day off, SWAT operators always need at the least, one backup option. You have flip up sights on your entry rifle because you have experienced the electronically generated dot of your choice fail without warning. I am betting that you will also have a sidearm secured to your plate carrier or holstered on your thigh along with a knife, strategically positioned for quick access if needed. Sniper missions require the same amount of redundancy. Calculators require light and/or batteries to operate. Slide rules can’t be read in darkness. Laser range finders sometimes fail like the red dot mounted on your match grade upper, not to mention their environmental limitations. Night vision (even the inexpensive units) can betray your location if your laser range finder is used in darkness. Every paranoid meth cook and wannabe terrorist can afford it. Suppose you had to navigate through water to get to your vantage point, will any of your battery-powered gizmos still perform, provided you even have them with you? Dead batteries will be a weak excuse to explain mission failure during a hot wash. If you do not have a plan for ranging in a situation that requires you to be totally blacked out, and your DOPE cards or slide rule are not in Braille, then you are left hoping that you never have to respond to such a scenario.
When we practice with the common formulas that are required to range objects with our optics, we do so with calculators or smart phones and pat ourselves on the back when we get the correct answers simply because we put in accurate data. You are setting yourself up for failure if you don’t have a plan that doesn’t include your downloaded shooter’s app. It takes some practice, but you can learn to operate battery-free by mentally breaking down the common formulas for range estimation. There are two commonly used Milradian ranging formulas. Most mil scope shooters choose one over the other, but each gives reliable answers.
Size of object in yards x 1000 divided by size of object in mils. Rule of 4s Method
Getting through the first part of the equation requires dividing the size of the object in inches by 36 to determine size in yards. Dividing anything by 36 on the fly is a bit intimidating. It would be simpler if we lived in a metric system friendly part of the world where we could easily convert centimeters to meters. It takes very little effort to convert 37 centimeters into .37 meters. But we don’t live there and I am willing to bet that a 20-inch wheel and a 36-inch-wide residential door will still be marketed as such for another generation or so. So, we must work with what we are presented. To avoid taking the troublesome 36 denominator head on, we can use simple multiplication and addition, using what I call the Rule of 4s Method. There are 36 inches in every yard, which unfortunately doesn’t correspond with the number of digits on our hands. That rules out the possibility of multiplying/dividing by 10 to get a metric system type of shortcut. But, most within our ranks are able to count in increments of 4, so let’s start there. 36 inches when divided by 4 equals 9. Therefore, every 4 inches represents 1/9th of a yard. 1/9th of anything is 11.1 percent.
- 4 inches = .111 yards
- 8 inches = .222 yards
- 12 inches = .333 yards
- 16 inches = .444 yards
- 20 inches = .555 yards
- 24 inches = .666 yards
- 28 inches = .777 yards
- 32 inches = .888 yards
- 36 inches = 1.00 yard
- Dividing 1-inch by 36 = .0277 yards
- .0277 can be rounded to .03
- 1 inch is rounded to .03
- 2 inches are rounded to .06
- 3 inches are rounded to .09
- 4 inches:
- Since every 4 inches reveal an easily identified yard equivalent, adding or subtracting beyond 3 is not necessary.
- If using 16 inches, subtract .03 for each inch needed to reach 15, which in this case is 1 inch (.444 - .03 = .414).
- .414 is sufficiently close to the actual .416.66 that you would have gotten with a calculator while dividing 15 by 36. A similar result could be found by starting at 12 inches (.333 yards) and adding .03 for each of the 3 inches needed to reach 15 (.333 + .09 = .423).
- At this point, we have satisfied the size of object in inches divided by 36 part of the equation.
- Next, move the decimal 3 places to the right to satisfy the x 1000 part of the formula (.423 x 1000 = 423).
- Then, divide by the size of object in mils. Using 2 mils as the measurement, the calculator would give us a distance of 208 yards for our battery powered 15inch object size (416.66/2 = 208.33). Our mental shortcut numbers of 414 and 423 yield comparable distances of 207 and 211 yards respectively, without any batteries.
- You can see from the example that rounding the last digit for expediency gives very small deviations. Do not round the other digits!
Size of object in inches x 27.77 divided by size of object in mils, Money Method
- Multiplying by 27.77 begs for a calculator’s assistance and makes dividing by 36 seem almost mundane. This equation can be domesticated somewhat by using what I call the Money Method.
- Start by breaking down the 27.77 into these smaller units: 25 +2.5 +.25 = 27.75, which is almost identical to 27.77. As in the first formula, rounding the last digit is acceptable.
- In keeping with the 5th grade math pledge, assign a monetary value in cents to the [B1] size in inches. If the object being ranged measures 20-inches, a grade school student could recognize that 20 quarters is worth 5 dollars. The 500.0 cents represented by the 20 quarters fits in the 25 position. That gives us 25 of the 27.77 needed.
- Next, solve the 2.5 part of the equation by moving the decimal one place to the left to get 50.0 or 50 cents. Add that to the 500 cents and we now have 550 cents (27.5 of the required 27.77).
- Now, solve the .25 by moving the decimal once again and we have 5 cents. Add that to the 550 and get 555 cents.
- Using battery generated technology with the 20 inches and the 27.77 multiplier gives us a nearly identical 555.4.
- With the size of object in inches x 27.77 satisfied, the remainder of the equation is identical to the preceding formula.
For both formulas, an object larger than 36 inches will require an extra digit in the size of object in yards and size of object in inches x 27.77 portion of the equations. Using 40 inches in the Rule of 4s formula, assign a value of 1 to the first 36 inches and .111 for the remaining 4 inches to get 1.111 total. After moving the decimal point 3 places to the right, the size in yards x 1000 measures 1111. Using the Money Method, 40 inches represents $10.00 (1000 cents). Then add 100 cents , then 10 cents and total for 1110 cents (1110).
All that remains now to determine the distance is to solve the size of object in mils portion of either formula which is fortunately much easier. I offer my preferred method as an example.
- Consider a 12-inch object, which yields 333 in both formulas. Using 1.5 mils as the measurement in the scope, divide 333 (size in yards x 1000 or size in inches x 27.77) by 1.5 (size in mils) to determine distance in yards to the object.
- Start by mentally multiplying the “size in mils portion” by 100 (1.5 x 100 = 150). That tells me that each 150 unit is equal to a distance of 100 yards. In this case, there is room for two units of 150 (150 + 150 = 300 which represents 200 yards).
- This leaves 33 of the original 333 remaining to be dealt with.
- Now, switch and mentally multiply 1.5 times 10 (1.5 x 10 = 15). Continue solving as before with each unit of 15 being represented as 10 yards (15 + 15 = 30 which adds 20 yards to the previous 200 yards and we get 220 yards).
- So far, this accounts for 330 of the original 333. That leaves only the final 3 of the original 333 unaccounted for.
- You have probably already guessed the value of remaining 3, which is 2 yards after another move of the decimal for a total distance or 222 yards.
We learn on day one of Basic SWAT training that the maximum range of an excuse is 0 meters. Failing to prepare is often the culprit when things do not go well. Not having a have a solid backup plan for a worst-case scenario in a tactical environment is a recipe for failure and also represents a big, fat, slow moving target for civil attorneys. If ranging calculations are incorrect, any subsequent wind or slope adjustments will be incorrect also. Devote and document some of your structured training time to develop your team’s skills. Realistic training is necessary to master your craft, and mastery is the standard required and expected, with or without batteries
[B1]