Calculating Minutes Of Angle (MOA)

[Preacherman]

I was watching a hunting show the other night and they were making a 675yd shot on a ram. The guy said that a 308 bullet at a certain distance was 9.0 MOA and that it calculated out to 90 inches. He said a 7mm at the same distance would only be 4.5 MOA and that was 45 inches.
So, based on those calculations each MOA is 10 inches. Does that sound right

 

[Perplexed]

Big discussion about MOA now taking place here: http://www.okshooters.com/showthread.php?129109-MOA-does-not-under-an-inch

 

[Robert871]

moa, minute of angle. you can look it up and you tube it or wiki it, and it helps under stand it. its a unit of measure based on basically a cone that projects outward. it just happens to be roughly approximate to one moa being near equal to one inch at 100 yards. by rough logic of calculation two moa would be two inches at 100 yards, or about four inches at 200 yards. for even experienced shooters it can be a tricky calculation to think up in your head on the fly. i am far from a master of understanding it or using it, but you can easily google, or youtube an explanation that will help put it into perspective.

edit. like i said, its roughly equal to an inch per 100 yards. although when you get beyond 500 yards the excess that we rounded off starts to accumulate and become noticeably important, the greater the distance, but 10 inches per 100 yards is not 1 moa, it would be 10 moa, and at 600 yards would be roughly a bit more than 60 inches.

 

[Larry Morgan]

MOA is minute of angle. It's an angular measurement. 1 MOA is 1/60th of a degree. 1 MOA is 0.01667 degrees or 0.291 milliradians. 100 yards = 300 feet = 3600 inches. 3600 inches * tan(0.291milliradians) = 1.047 inches.

So, this produces a circle with a 1.047 inch RADIUS at 100 yards.

You can work that formula backwards too, if you have the radius and distance and want the MOA.

Yay, trig!

 

[Robert871]

MOA is minute of angle. It's an angular measurement. 1 MOA is 1/60th of a degree. 1 MOA is 0.01667 degrees or 0.291 milliradians. 100 yards = 300 feet = 3600 inches. 3600 inches * tan(0.291milliradians) = 1.047 inches.

So, this produces a circle with a 1.047 inch RADIUS at 100 yards.

You can work that formula backwards too, if you have the radius and distance and want the MOA.

Yay, trig!

what that guy said.
take that equation, your ti-84, and never worry about it again.

 

[Perplexed]

Guys, if you go to the link I provided, you'll find all your answers and then some

 

[HMFIC]

I was watching a hunting show the other night and they were making a 675yd shot on a ram. The guy said that a 308 bullet at a certain distance was 9.0 MOA and that it calculated out to 90 inches. He said a 7mm at the same distance would only be 4.5 MOA and that was 45 inches.
So, based on those calculations each MOA is 10 inches. Does that sound right

No sir, it does not sound right.

He's likely trying to say that the different rounds were capable of that level of accuracy, but there are too many other factors involved to say that as a general statement.

 

[Thorgrim]

That doesn't make sense. My .308 has a 26" barrel. Shooting 175gr. FGMM, I need approx. 17 MOA dialed up. My MKIV has the M3 turret (1moa elev.) for 675 yards. I didn't factor in elev, temp....
9 MOA elevation will take me to about 475 yards.

The other way I could look at your statement is that when the ram was viewed with a MOA reticle it measured 9 MOA which would make it just over 60" tall.....sounds kind of big. Here's the formula.

size"/moa reading x 100 = range in yards.

Something doesn't jive here. By the way if you want to learn more about long range shooting go to Badlands in Grandfield OK. Bobby and Steve do a great job teaching this kind of material.