Measuring MOA

ArmySon

Staff Alumnus
How do you measure MOA out at 200 yards, 300 yards, etc?

1" at 100 yards has always been considered MOA. Would 2" @ 200 yards be considered MOA then? 3" @ 300 etc etc.

I was fine tuning some reloads and totally forgot how to measure MOA beyond 200 yards. Please help my momentary brain cramp ;)
 

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Karsten

Moderator
We just had a lenthy discussion on another board about this...This straightened me right out Karsten,
Let me see if I can do this in a semi clear manner, using generalities.

You seem to be thinking in inches of elevation, and probably "clicks" on the scope. Many shooters inexperienced (NO FLAME) in long range shooting do this.
Competition and long range shooters think in MOA, as you've observed, and it can be confusing trying to do the mental gymnastics. An inch is an inch no matter what distance, and an MOA is sorta variable.

MOA roughly equals 1 inch X Distance in yards
1 MOA at 100 yards = 1 inch
1 MOA at 500 yards = 5 inches
1 MOA at 1000 yards= 10 inches.

So when I said 30.5 MOA I actually allowed for 305 inches of elevation change at 1000 yards.

By doing the mental math in MOA a shooter can quickly dial in adjustments to his/her scope to take a shot.

So my 30.5 MOA would be two complete revolutions on the scope as opposed to counting 122 clicks and missing one or two of them in the process. It's just a faster measurement mentally and physically. Those indexed target turrets really help in doing this quickly.

Also helpful is getting away from the mindset of "where does it shoot if I'm at XXX at 100 yards". What needs to happen is that you have your 100 yard zero. To shoot 200 yards you learn via ballistics program(approximate)
or by actually shooting the data (accurate), how many MOA to dial into the elevation setting on your scope.

This is done for each range you would expect to shoot. Most of us have data every 100 yards to 1000 yards. Some of us have it in 25 yard increments all the way back to 1000 yards. Depending on what you are going to do, the data becomes valuable.

Since you're playing with the JBM program, you probably noticed that things like elevation above sea level, temp, barometric pressure all have effect on bullet flight.
Alot of us shoot data for each of the seasons, and travel to different ranges in the country to shoot at various altitudes, temps, atmospheric densities.

As Boltripper (who BTW is a very good rifleman) noted, alot of us compete and attend classes. It's just more data for the log book.

Also remember that most longrange shooters handload for their rifles. Using factory data gives less than impressive results on the ballistics comp. Using actual data shot over a chronograph gives much more impressive numbers in alot of instances.

On the subject of 1200 yard shots, yes the bullet does come down at a steep angle past 1000 yards. From shooting on the tank trails at Ft Hood I can tell you that by 1400 yards the 308 is pretty well over and done with for reliable first round target strike. Some of the delta guys I've seen can make it look good......I sure can't.

Hope all this rambling made some sense of things. Best to all.

------------------------------------------------------------------------


Hope that helped.

Karsten
 

Mal H

Staff
Yep, you've got it right Son. Since the angle of measurement doesn't change with distance, the size of a MOA would be double/triple at double/triple the distance, no matter what the distance. The same is true for any fractional distances, i.e., 1.5 X D would yield 1.5 times the MOA size, etc.

However, since you're going out to long ranges, it's best to use the exact size for a 100 yd MOA - 1.04" since the fraction adds up to a significant amount beyond 200 yards.
 

ArmySon

Staff Alumnus
So, if you go roughly by 1" at 100 yards, then the following is correct?

Since MOA stands for Measurement Of Angle which is a subdivision of a degree. Since there's 360 degrees in a true circle...

4 quadrants = 1 circle
90 degrees = 1 quadrant
60 minutes = 1 degree
60 seconds = 1 minute
21,600 minutes = 1 circle

Now it's coming back to me!

1.047197551" at 100 yards,
 

Mal H

Staff
Ol Korrect, except that MOA stands for Minute of Angle. Measurement of Angle would be a somewhat nebulous term.
 

ArmySon

Staff Alumnus
I guess "Minute of Angle" is more widely accepted as the correct term but breaking it down in trigonometry, it would be correct as measurement of angle.

Either way, many thanks!
 

C.R.Sam

New member
¿ Would not measurment of angle be the measurment of angular difference between whatevers: And the results of that measurement expressed in minutes of angle ? Thereby having both terms correct when used in the proper context.

Sam....picky ol fart, nosey too.
 

James K

Member In Memoriam
Pardon me, but how can anyone take something so simple and make it so complicated? I guess it's part of human nature.

Jim
 

Kaylee

New member
naah, I think he just wanted to show off that incredible group, and this was a subtle way to do it ;)

Touching holes at 200 yds? Right on!!
What are you, some kinda human machine rest?


-K
 

ArmySon

Staff Alumnus
Nah, it's called a "lemon" Remington (i.e. http://www.thefiringline.com/forums/showthread.php?s=&threadid=74476)

Jim

Some of us that 'complicate' things enjoy the mathematics behind various terminology, solutions, mechanics, etc. If an individual wishes to go by 1" @ 100, 2" @ 200, etc I'll never think any different.

Likewise if an individual is perfectly content with pulling the trigger and making the firearm go bang. Whereas, there are people who enjoy the mechanics in making the firearm go bang.

Complicated nature? Maybe. Curious? Definitely.
 

Karsten

Moderator
Geez...can we get back to English and the basics here :confused:
Next we shall be figuring out which is the higher speed condom....
This wasn't Math, damn..I hated math, I still hate math :p
Then that other stuff where AxY=Z+b-F+sex means great groups.
I just don't get it....

Karsten

Oh, nice group by the way.....I guess your wife was happy too :p
 

C.R.Sam

New member
Group...what group...............oh THAT group.

Nice group Son......looks like fairly typical barrel warming on 4 and 5. You do hold solid.

Sam
 

ArmySon

Staff Alumnus
Sam

I kicked myself for not waiting a bit for the barrel to cool down. It would've been a nice 3 shot group though :(

I have other targets that are almost all touching out @ 200 yards. It's amazing what reloads can do to group size! The best group I had with factory ammo was slightly under 2" out at 200!
 

echo3mike

New member
Can't help ya...

with the MOA thing. Nice group! And I was (almost) satisfied with groups like that @100yds.


Oh, well...back to the bench!
 
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