Ranging


PDA






precisionrifle14
February 1, 2012, 01:29 AM
Can someone give and explain a simple formula for ranging using mil-dot scopes. Is there a certain magnification the scope should be used on to range? What are some measurements of common things to range against?

If you enjoyed reading about "Ranging" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
timothy75
February 1, 2012, 03:24 AM
Yes there is a certain power, it should be in the instruction book for the scope along with other information.

War Squirrel
February 1, 2012, 03:54 AM
As timothy said, your scope manual will say at what magnification the mils are most true at. If you can't find the manual, check the scope manufacturers website.

Time for War Squirrel's Crash Course in Mil Dot Ranging.


Remember this. A mil subtends about 1m at 1000m. Thus, at 100m, a 1m target will be 10 mils wide.

Using our information, we can devise an easy way to test how accurate your mils are, if you own a laser rangefinder. Cut out a piece of cardboard exactly 1m square, and lase the distance to the target. Move back, staying as level as possible with the cardboard, until you are exactly 100m away. Then, fiddle with your scope magnification until the target measures 10 mils exactly. You can then add a new witness mark to your zoom dial if needed. REMEMBER, A REAR BAG IS YOUR FRIEND! It is VERY hard to get accurate mil measurements without a rear bag or bench.
If you trust your mils, then this test isn't really necessary, but it is a great hands-on way to familiarize yourself with mils.


Now then, down to the fun math. :uhoh:
The basic mil-to-range conversion ratio is as follows:

(size of target in meters) x 1000
------------------------------------- = range to target in meters
(number of mils)

OR


(size of target in yards) x 1000
-------------------------------- = range to target in yards
(number of mils)



So, if we had a silhouette target, with a width of .5 meters from shoulder to shoulder, and measuring .7 mils, then:
(.5 x 1000)/.7 = 714.3m
meaning, the target is about 714 meters away. Nice!


Let's try another one. The same target with a width of .5 meters from shoulder to shoulder, and measuring exactly 2 mils, then:
(.5 x 1000)/2 = 250m
meaning, the target is about 250 meters away. This would be a much easier shot than the last one.




Note that the same formula works for both types of measurements. Also, being precise with your mils is very very important as the range increases, or when working with small targets. Again, the rear bag will save you much headache at either close or extended ranges. Also, you may wish to consider stuffing a small solar calculator and tape measure into your range bag for this sort of thing.


Now then, cut out targets of various MEASURED sizes and place them at unknown distances. Try to solve them with mils and test them against your laser rangefinder. It is easy to get rather good at this with a little practice. It is also a good way to test out a dope card, if you wish to make one.
Have fun and be safe!



COMMON HEIGHTS OF US OBJECTS (FT-----METERS-----YARDS
Mailbox post (to bottom of box)------3.5-4----1-1.2------1.2-1.3
Utility pole--------------------------33-------10--------11
standard 18" car rim----------------1.5------.45--------.5 (this one varies, but most are similar in size)
average US man height ----------------5.8------1.7--------2
Standard US door------------------6.6-------2---------2.2
US dumpster-----------------------6--------1.83-------2 (length, because most are 6' long but vary in height)
bicycle----------------------------5.8------1.78-------1.95 (length)
AK47-----------------------------2.87-------.87-------.95 (length)

Sergeant Sabre
February 1, 2012, 06:57 AM
To super-simplify the above post: The average size of the target (in meters) x 1000, divided by the number of mils, equals range in meters

So, if you have a man that takes up 4 mils, head-to-toe (avg size rounded to 2m)

(2 x 1000) / 4 = 500m range

precisionrifle14
February 1, 2012, 11:45 PM
Thanks guys, I'm off to practice!!

taliv
February 1, 2012, 11:50 PM
note the ranging sticky thread for practice

War Squirrel
February 3, 2012, 02:52 AM
Have fun, precision. Glad we could help.

mljdeckard
February 3, 2012, 03:02 AM
I terped for some Marines in Africa a few years ago, and I got to play on the range with their snipers for a couple of days. They told me the secret to ranging shots in Iraq became simple when they realized that all passenger vehicles in Iraq use 14" rims. This meant that any time there was a car in the sight picture, they had an object of known size to compare to. Even if the wheel is turned a bit, you can still measure it from top to bottom.

War Squirrel
February 4, 2012, 12:31 AM
Ha, thanks for that info mljdeckard. That's an interesting tidbit.

If you enjoyed reading about "Ranging" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!