Long range shooting questions

[gunnutery]

I am kind of slow at math sometimes so please correct me if I'm wrong.

I've had a Savage 10FP .308 for about ten years now and would like to get into some longer distances than 200 yards (which is all that is currently available to me). In reading some recent threads I was reminded that with a 1/4 MOA scope (@100 yards) at 200 yards it will be 1/2 MOA, 300 will be 3/4 MOA and at 400 yards it will be 1 MOA adjustments.

Will 500 yards be 1 1/4 MOA, 600 yards 1 1/2 MOA, 700 yards 1 3/4 MOA and 800 yards 2 MOA adjustments? Assuming that I'm focused on a target that is at those distances? Is my math correct there?


Unfortunately I don't have any more yardage lined up to practice this knowledge yet. Thanks for any and all help.

 

[Kurt_D]

No, that is not correct. A quality scope with 1/4 MOA adjustments has 1/4 MOA adjustment from 25yds to 1000yds+. It's consistant.

Where you're getting confused is MOA is a measurement of angle (like degrees). Picture a triangle starting infront of you. It gets wider the further away you go however the angle stays the same, same thing with the scope.

So 1 MOA at 100yds = 1 MOA at 1000yds; However 1 MOA = about 1 inch at 100yds and 2 inches at 200yds and 10 inches at 1000yds, etc. (note: while not extact but close enough, dividing your yardage by 100 will give you how many inches 1 MOA equals at that range.)

Example: You need to move your point of impact at 300yds 6 inches; You need to move 2 MOA which is 8 clicks on a 1/4 MOA scope. You need to move your point of impact at 1000yds 20 inches; you again need to move 2 MOA which is 8 clicks on your 1/4 MOA scope. Yes, your adjustments are extactly the same.

ETA: Your shooting a target at 625yds and need to move your point of impact 10 inches right to strike center. At 625yds 1 MOA = 6.25 inches (625/100). You need to move 1.6 MOA to the right (10/6.25). You need 6 clicks on a 1/4 MOA scope to get there (4 clicks per 1 MOA; 6 clicks = 1.5 MOA = 9.3 inches and 7 clicks = 1.75 MOA = 10.9 inches; it's in the ballpark).

 

[rozziboy18]

+1 kurt,

a moa stays the same out from 100-1000+

technical junk,


4 clicks on the scope, for most scopes,= 1moa
8 clicks= 2moa
13 clicks= 3 1/4 moa
ect....

moa yards inches

1 100 1.047
1 200 2.094
1 300 3.141
ect....

in a nut shell a moa scope alows for quick adjustment for engagment, say you have a target at 600 yards and your zeroed at 100 and at 600 yards your bullet drops 117.5 inches at that range heres the math you need to follow

6 x 1.047= 6.282 ( meaning 1 moa adjustment at 600 yards = 6.282 inches in bullet impact change

then 117.5 devided by 6.282 = 18 3/4 moa

so then you would adjust your elevation dial up 18 3/4 moa or 75 clicks up.

so long story short its easyer and faster to 18 3/4 moa on the scope than 75 small clicks

hope this helps in some way,
brandon

 

[ms6852]

The above information is correct. It is a quadratic equation. Do a search for quadratic equations and you will understand it better.

http://www.charliedatuna.com/airgun_docs/Minute of Angle (MOA).doc

http://www.ultimatesniper.com/Docs/46.PDF

The 2nd link should make it a little clearer.

 

[gunnutery]

Thanks for setting me straight guys.

 

[blackops]

750 yds......1.047 MOA @100yds......7.5 X 1.047=7.8525.......then take the amount of inches your bullet will drop at 750 (180" for example) and divide it by7.8525. So 180/7.8525=22.922636. So apply 23 MOA to your scope and pull the trigger. That is after you have calculated the wind. That's another thread though.

 

[unit91]

The above information is correct. It is a quadratic equation. Do a search for quadratic equations and you will understand it better.

Well...trigonometric. We're really just talking sin/cos/tan here.

 

[Uncle Mike]

Why convert from inches to MOA and then back to inches.....?

10" at 100y is just that, 10", it is also at 1000y, it is 10"!

If you need to move your point of impact 10" at 100y with a scope that adjust by 1/4"@100y, which the majority of them do, then it is pretty simple math....

10"(the amount you need to move your point of impact) / .250"(the amount your scope moves the point of impact PER CLICK) = 40 (clicks needed to move your impact 10" at 100y)

10"/.250" = 40

At 1000y, you observe you need to move your point of impact 10".....

First you have to find how much each click on your 1/4" per 100y scope will move the point of impact at 1000y.

.250(The amount your point of impact moves per click, at 100y) X 10(For 1000y) = 2.5"( the amount each click will move your point of impact at 1000y)

.250 x 10(for 1000y) = 2.5"

Then....10"( the amount you need to move your point of impact at 1000y) / 2.5"(the amount each click moves your point of impact at 1000y) = 4(clicks needed to move your point of impact 10" at 1000y, with your 1/4"@100y scope)

10" / 2.5" = 4

If your equipment adjust in inches, then use inches, why use MOA for the adjustment values with this particular equipment?


If you use MOA for this particular problem, you'll first convert inches to MOA and then back to inches....too much ciphering! hehehehe

 

[benEzra]

If your equipment adjust in inches, then use inches, why use MOA for the adjustment values with this particular equipment?

Because the equipment actually adjusts in MOA, even if it is labeled in inches. Still, either method works; it's basically the same calculation by a different name.

 

[blackops]

If you are anal about accuracy do the equation. If your not then utilize inches instead of MOA. I find utilizing MOA puts me on target quicker both mentally and physically.

 

[rozziboy18]

Uncle Mike,
Because at 1000 yards 10 inches is 10 inches but a moa is 10 inches. And when your factoring 300 inches or more of drop that's 90 little clicks you get to count and God help you if you loose count. But that 30 moa you can visually count on the scope. Much fast harder to screw up

 

[Uncle Mike]

Because at 1000 yards 10 inches is 10 inches but a moa is 10 inches. And when your factoring 300 inches or more of drop that's 90 little clicks you get to count and God help you if you loose count. But that 30 moa you can visually count on the scope. Much fast harder to screw up

How's that?

That turret dial still has to move 90 little clicks, no matter which unit of measurement you use. So what do you do, you can memorize how many inches, or MOA one full rotation of the turret dial will move your POI at a particular range, that'll help keep the counting down... or how many inches or MOA a 4-click 'section' moves your POI...still, the calculator has to come out, unless of course you have really detailed range cards.

So, how many clicks, or how many complete rotations of the turret dial does it take to accomplish 30 MOA?

 

[rozziboy18]

see numbers!!!!!, most tactical scopes have VISUAL tick marks for moa's, you can count visualy and adjust faster that way both methods or right this one is just a little faster regardless you have to do math.

349 inches of drop at 100 yards for say

1 MOA = 10.47 inches impact change at target on all scopes

349 (divided by) 10.47= 33.50 moa
then all you have to do is visually count the numbers on the dial till you hit 33.50 moa and presto you there!

 

[xphunter]

"So, how many clicks, or how many complete rotations of the turret dial does it take to accomplish 30 MOA?"

Depends on the optic.
Leupold VX-3's and Mark 4's have 15 MOA per revolution. (2-full revolutions)
Some of NF's have 10 MOA per revolution. (3-full revolutions)
One scope I have has 20 MOA per revolution. (1 1/2 revolutions)

 

[gunnutery]

If your equipment adjust in inches, then use inches, why use MOA for the adjustment values with this particular equipment?

Sorry for the dumb question, but what is the difference between inches and MOA? I thought they were essentially the same. It's pretty obvious how little scope work I've done

 

[USP45T]

The value (in inches) that 1moa is equal to changes with your distance to target. At 100yds, 1moa = 1" (1.047" actually but we'll drop the .047 right now). So at a 100yd target distance 1moa = 1". At 200yds, 1moa = 2". At 300yds, 1moa = 3"...and so on. So if your scope has 1/4moa adjustments and you adjust it 4 clicks, you move your point of impact 1" and 100yds, 2" at 200yds, 3" at 300yds... and so on. You're making the same adjustments (clicks) on your scope (4) but the POI is varying with distance to target. Going to shorter distances...at 50yds, each one of a scopes 1/4moa adjustments move the POI 1/8th of an inch. At 25yds, each 1/4moa click moves POI by 1/16th of an inch.

ETA: I'll expand (confuse) a little more. If you were to setup multiple targets in a straight line from the shooter and you put a target at 100yds, 200yds and 300yd, and then took 1 shot. Then you go mark where the shot is on the 100, 200 and 300yd targets. If you and your rifle could repeatedly hit the same spot over and over, you adjust your 1/4moa adjustable scope 4 clicks. On your 100yd target, you see that your POI moved 1". On your 200yd target, your POI moved 2"...and so on.

 

[USP45T]

Getting away from thinking about inches some more, my scope is metric. At 100 meters, each click adjustment moves the point of impact 1cm. At 200m, each click moves the POI 2cm. At 300m, each click moves the POI 3cm...an so on. At 50m, each click moves POI 0.5cm. At 25m, each click moves POI 0.25cm.

 

[Uncle Mike]

This may help.... I found it somewhere, it is a pretty good layman explanation of this phenominom known as MOA! hehehe

MOA is simple. Its a minute of angle. Its the same minute of angle no matter how distance you are at. So if your chart reads 5 MOA at 300 yards, no matter what adjustment one "click" is equal to on your scope you know you have to dial enough to equal 5 MOA.

If your scope is 1/4 MOA per "click" then its 4 clicks per MOA times 5 for a total of 20, 1/4 MOA "clicks" or adjustments to equal 5 MOA. If your scope has 1/2 MOA adjustments then its 2 "clicks" per MOA time 5 for a total of 10, 1/2 MOA "clicks" or adjustments to equal 5 MOA. If you needed to adjust another 8 MOA to go out to 500 yards, its the same process. One minute of angle is still the same 4 "clicks" per MOA for a 1/4 MOA adjustment scope or 2 "clicks" per MOA, for a 1/2 MOA adjustment scope.

If you dope is in MOA you don't have to convert anything. It becomes more complicated when you try to equate a linear measurment with it, because the further you go out the wider the distance from one side of the angle to the other becomes. Its still not very complicated, but if you think in terms of the adjustments that your scope has it will be much easier for you.





Notice it says "if your chart says", what I was getting at, and we see it time and again at the ranges and shoots, someone knows what he knows, he knows he needs to come up 300" to be on at 1000y, he has no chart, he has no computer, all he has is a ballistic chart from some ammo manufacturer, so how does this guy know, just by looking at his ballistic chart and 'ticks' on the turrets how much to crank that turret?

Still, even with knowing all this, the calculator has to come out, unless of course you have a mind like a steel jaw trap!

For most scopes, 4 clicks will move your POI 1"@100y or 10"@1000y, so, yes just use the numbers on the turret...but the math is still the same, whether your thinking in MOA or inches.

Hey, let's move on to MIL's, that ought to be funner! Yeah, I did say...funner!

 

[aubie515]

Or you could just get a ballistics program on your PDA or cell phone and plug in numbers to get the information that you want for your specific load.

 

[gunnutery]

Thanks for everyone's help. I've read through the posts multiple times just to make sure I'm getting it.

Thanks again.

 

[MinnMooney]

Because the equipment actually adjusts in MOA, even if it is labeled in inches. Still, either method works; it's basically the same calculation by a different name.

This is a misnomer. Even those scopes that are labeled as 1 click = 1/4" or 1 click = 1/4 moa do not nessisarily actual change the POI that distance. There are errors in the gearing that only make them close - most of the time - or really bad.

Please see my thread in "Rifle Country" titled : "Scope specs and ballistic chart accuracy."