CM, Mill, and Cant

[FS1]

I am posting this here because being a novice at long distance shooting, I am assuming that any questions I have on Marksmanship are stupid ones.

S&B 5-25x56 elevation adjustment shows 260 CM. I assume this equates to 2.6 meters at 100 meters. How much of that adjustment do I lose if I only used a 20.4 MOA cant instead of a 40 MOA cant.

Also I assume that because my Reticle (H2CMR) is 10 CM per mil the .1 mrad ajustment equates to 1 CM.

Am I on the right track or just living in a state of confusion?

Thanks

 

[Rob01]

First off, stop thinking in cm and meters, except for your range you are shooting. 26 mils is what you have. That is equal to about 90 MOA, 26 x 3.44(the number of MOA are in 1 mil) = 89.44 MOA. You can run a 20 MOA base without a problem and should have about 65 MOA of up elevation.

1 mil has 10 .1 mils in it. Don't think in cm. When you run your data for your come ups run them in mils and dial on or hold what it says. If you need to make a correction look through the scope and use the ruler in front of your eyes, which is the reticle, and see how much you need to correct and then dial on or hold the correction.

The sooner you stop thinking in cm or meters the easier using the scope will become because linear measurements like cm and meters will just confuse you. Don't make it more confusing.

 

[FS1]

First off, stop thinking in cm and meters, except for your range you are shooting. 26 mils is what you have. That is equal to about 90 MOA, 26 x 3.44(the number of MOA are in 1 mil) = 89.44 MOA. You can run a 20 MOA base without a problem and should have about 65 MOA of up elevation.

1 mil has 10 .1 mils in it. Don't think in cm. When you run your data for your come ups run them in mils and dial on or hold what it says. If you need to make a correction look through the scope and use the ruler in front of your eyes, which is the reticle, and see how much you need to correct and then dial on or hold the correction.

The sooner you stop thinking in cm or meters the easier using the scope will become because linear measurements like cm and meters will just confuse you. Don't make it more confusing.

Thanks Rob sounds like good info. Sure is a bit easier to think in mils rather than CM.

How accurate will I get my range using the reticle? And as you reach out, does the ranging accuracy change as the range increases?

One last stupid question. Using ballistics AE does the program calculate based upon air density? My first guess would be yes it derives that from temp, hum, and altitude. How close does the software get you to the ideal firing solution?

 

[djskit]

You can turn the air density feature/atmospherics on and off in Ballistic AE.

 

[Rob01]

Thanks Rob sounds like good info. Sure is a bit easier to think in mils rather than CM.

How accurate will I get my range using the reticle? And as you reach out, does the ranging accuracy change as the range increases?

One last stupid question. Using ballistics AE does the program calculate based upon air density? My first guess would be yes it derives that from temp, hum, and altitude. How close does the software get you to the ideal firing solution?

How accurate is up to how well you can break down the reticle. If you can get down to .1 mil which should be simple with the H2CMR reticle it will be fairly accurate but if you can break it down to .05 mils then you will be more accurate. With practice and that reticle it can be done fairly easily.

The farther you go out the more difficult it is to get a very accurate range using the reticle due to mirage and just plain being able to clearly see the target edges. Practice can make it more accurate but most start losing accuracy to be within 10 yards at about 700-800 yards. The more off your range estimation is the more difficult it will be to hit as you might drop rounds short or over the top but luckily with a .260 it's fairly flat shooting so you can be off a little. That said try and be as accurate as possible and practice.

Also you can use the reticle to make shots by holding elevation and/or windage. Practice that too.

I don;t use Ballistics AE but DJ covered it I believe.

 

[Johan L.]

I am posting this here because being a novice at long distance shooting, I am assuming that any questions I have on Marksmanship are stupid ones.

S&B 5-25x56 elevation adjustment shows 260 CM. I assume this equates to 2.6 meters at 100 meters. How much of that adjustment do I lose if I only used a 20.4 MOA cant instead of a 40 MOA cant.

Also I assume that because my Reticle (H2CMR) is 10 CM per mil the .1 mrad ajustment equates to 1 CM.

Am I on the right track or just living in a state of confusion?

Thanks

mrad, milliradians, has nothing to do with meters, yards or whetever length or distance. It's an angle and it is one thousand of a radian. The formula is really simple: angle (in radians)= length of arc / radius.

So just multiply the distance (radius) with the angle and you get a very good approximation of the horisontal ( or vertical or whatever) distance at the target. 0.1 mrad att 100 meters equals to 0.0001 x 100 = 0.01 meters, i.e. 1 cm. 0.1 mrad at 100 yards equals to 0.0001x100 = 0.01 yards and now you wish you were using the metric system....

It's an approximation as it is not really the straight vertical, or horisontal, distance but the length of arc at the target. But with such small angles it 's safe to say that it's the same thing.