Picture yourself getting the jump on a big prairie dog town. You crest a hill, lay your trusty .22 across a fencepost, and peer through your scope. It’s pretty far. You might need to aim a little bit high. If only you paid more attention to the MOA vs MRAD debate.
Experience might tell you that your bullet hits a certain distance low at 150 yards and a little more at 200 yards, but “a little low” doesn’t give you much to work with, especially when you don’t even know the distance to your target. Even if you knew exactly how many inches low it was at the distance you’re trying to shoot, could you really picture that in your scope with any degree of accuracy?
What you need is a way to make precise, calculated adjustments to compensate for proven ballistic performance. That’s where minutes of angle (MOA) and milliradian (MRAD) come in. These concepts are absolutely essential to shooting well — even if all you’re doing is zeroing your pistol’s red dot — and figuring them out might be easier than you think.
What are MOA and MRAD?
Both MOA (minutes of angle) and MRAD (milliradian) are methods of measuring angular units. Bullets aren’t laser beams, so we all understand that we have to aim high to engage targets that are far away from us. Rather than calculating bullet drop to inches, creating a mental estimation of what that looks like, and aiming at a point in space above our desired point of impact, we use these angular units to get on target.
Both methods are more than capable of facilitating precision shooting. They’re not interchangeable, though, so your rifle scope, reticle spotting scope, ballistic tables, and any software you use will need to be on the same page. Eventually, you’ll learn to think in MOA or MRAD and be able to make better adjustments on the fly.
MOA: What You Need To Know
The majority of all sighting systems (scopes, red dots, holographic sights, and iron sights) sold in the U.S. use MOA because this unit works well with imperial units — specifically inches and yards.
What is MOA?
There are 360 degrees in a circle and 60 minutes in a degree. One minute (MOA) equals 1/21,600 of a circle.
At 100 yards, one MOA equals 1.047 inches. Since it’s angular, the same one-MOA angle expands to 2.094 inches at 200 yards, 3.141 inches at 300 yards, and so on. Moving your point of aim one MOA shifts your point of impact 1.047 inches at 100 yards.
That’s not very precise, so most optics use quarter-MOA adjustments. If your scope turret is labeled “one click = 1/4 MOA,” you’ll be able to refine your point of impact in 0.26-inch increments at 100 yards.
By using 1/4-MOA adjustments, we divide a circle into 86,400 slices, and each click of your turret moves your point of aim 0.004 degrees.
What About “Shooter’s MOA?”
Many people use what’s called “Shooter’s MOA,” which rounds MOA to the nearest quarter-inch. That’s why you’ll hear people say that one MOA equals one inch at 100 yards. They’ll equate one click of a 1/4-MOA turret to 0.25 inches at 100 yards rather than 0.26 inches at 100 yards.
It’s not exactly correct, but it’s close enough in some cases. At longer distances, this shortcut will catch up with you.
At 1,000 yards, .308 Win might drop 393 inches. Using MOA, your come-up in that situation (393 inches / 10.47 inches per MOA at that range) would be 37.5 MOA, and your point of aim would be 393 inches above your point of impact, matching bullet drop exactly.
If you were using Shooter’s MOA, your come-up would be 39.3 MOA (393 inches / 10 inches per shooter’s MOA at that range). Because scope turrets use actual MOA rather than Shooter’s MOA, your input of 39.25 MOA (the closest setting to 39.3) would result in a point of aim 411 inches above the center of your target and cause your bullet to impact 18.5 inches high. Unless you have a massive target, that’s a miss.
|Range in Yards||1/4 MOA||1/4 Shooter’s MOA|
|100||0.26 inches||0.25 inches|
|200||0.52 inches||0.5 inches|
|300||0.79 inches||0.75 inches|
|400||1.05 inches||1.00 inches|
|500||1.31 inches||1.25 inches|
|600||1.57 inches||1.5 inches|
|700||1.83 inches||1.75 inches|
|800||2.09 inches||2 inches|
|900||2.36 inches||2.25 inches|
|1,000||2.62 inches||2.5 inches|
MRAD: What You Need To Know
Outside of the U.S., shooters generally prefer to use MRAD over MOA. Interestingly enough, American military snipers also use the metric-based MRAD system; most precision shooters do, too.
What is MRAD?
Instead of using degrees, we can divide a circle into 6.283 radians. Inside each radian are 1,000 milliradians (mils, for short) for a total of 6,283 mils in a circle. Random, right? Damn Europeans.
There’s a method to this madness because one mil equates to 10 centimeters at 100 meters.
In the same way that we don’t make adjustments in whole MOA, we don’t make them in whole mils, either. Scopes turn in 1/10-mil increments, so one click on your turret translates to one centimeter at 100 meters.
A scope’s 1/10-mil adjustments divide a circle into 62,832 pieces, and each click moves your point of aim to 0.006 degrees.
When you range targets in yards, using MRAD can feel clumsy.
|Range in Yards||1/10 MRAD|
But when you range targets in meters, using the 1/10 MRAD adjustments on your scope turrets is straightforward.
|Range in Meters||1/10 MRAD|
MRAD vs MOA: Which Should You Use?
Knowing that both systems are effective doesn’t make your scope-purchasing decision any easier. There has to be a reason some shooters prefer one over the other.
Why You Should Use MRAD
Using the 100-yard example, a typical MOA scope will let you make adjustments in finer increments. Remember that, at 100 yards, 1/4 MOA equals 0.26 inches while 1\10 mil equals 0.36 inches. But if MOA is more precise, why do snipers and competitive shooters almost universally prefer MRAD?
In the real world, there is a practical limit to the degree of precision we’re capable of extracting from a shooting system (our rifle, scope, and ammunition).
“On the milliradian optic, I’m doing 1/10 of a mil click in whatever direction, that’s going to equal roughly 2.5 inches at 700 yards,” Eliasson said in the Vortex Edge podcast. “If I do that same click on a 1/4-minute adjustment minute of angle optic that’s about two inches — a little under, I think it is. So it’s like two, 2.5 at 700; can you shoot that good?”
Both MOA and MRAD deliver the precision you need, and MRAD scopes can save time by making adjustments in slightly larger leaps, as Eliasson discovered during his time as a Marine Corps scout sniper.
“We got the 1/4-minute adjustment optic on our gun, and I felt like I was just adjusting for days,” he said. “It was just click, click, click, click, click, click to get where I needed to go. I thought that was kind of hindering us to a degree.”
The base-10 nature of MRAD can also make life simpler when you’re shooting under pressure.
“If somebody says, ‘Come up 0.7’ that’s seven clicks,” James Hamilton, host of the Vortex Edge podcast, said. “And if they’re like, ‘1.7’ that’s 17 clicks. But if somebody says, ‘Come up 2-3/4 MOA’ I’m like, ‘Okay one click is 1/4 MOA, so that’s four clicks per one MOA, so that means four times two is eight, plus 3/4 is three, eight plus three is — you know?”
Simply put, MRAD scopes get us inside the margin of human error with less time spent converting quarters to clicks, counting tiny hash marks, and fiddling around with our scope turrets. Since most competitive shooters use MRAD, that route will also make it easier to learn from others if you have ambitions of getting started in long range shooting.
Why You Should Use MOA
Most shooters who prefer MOA optics probably appreciate the unit’s relative correlation to inches and yards rather than adapting to the metric system.
“As Americans, if you were born and raised here, we tend to think in inches, and it’s really hard to associate what 10 centimeters looks like,” Eliasson said. “Our brain kind of wants to think about it in 10 inches, not 10 centimeters.”
The combined market for MOA hunting scopes and low-power variable optics with a BDC (a bullet drop compensator reticle like the one in the Trijicon ACOG) is probably larger than it is for MRAD scopes. Red dot optics and holographic sights almost universally use MOA. That alone might be enough to sway you, especially if you don’t need a fancy mil-dot reticle.
“Some of our optics that I’m thinking of are very, very well-suited for hunting and they’re just not even available in MRAD,” Hamilton said. “In my head, I’m thinking getting the right optic is more important than getting some super-duper special unit of measurement.”
The reality is that the advantages of MRAD scopes don’t matter at the distances most people shoot. Plenty of hunters and recreational shooters do just fine by zeroing at 50 yards, having a usable point of aim out to about 200 yards, and falling back on Shooter’s MOA in a pinch.
Use Your MOA Or MRAD Reticle to Estimate Range
You can use both MOA and MRAD to perform useful calculations in the field if you have a technical reticle. Knowing how to use these formulas will help you get the most out of your scope.
Make the resulting adjustments by dialing your turrets or using a holdover based on the subtensions in your reticle.
Yards to target = (size of target in inches x 95.5) / size of target in MOA
Yards to target = (size of target in inches x 27.77) / size of target in mils
To use these formulas, you’ll need to know the size of your target in inches. Between that known size, the size of the target in MOA or MRAD as measured with your reticle, and the appropriate constant (95.5 for MOA or 27.77 for MRAD), you can determine the distance to your target in yards.
Size of target in inches = (yards to target x size of target in MOA) / 95.5
Size of target in inches = (yards to target x size of target in MRAD) / 27.77
The size estimation formula is based on the range estimation formula; it just solves for a different variable. This is particularly useful for hunters who want to gauge a game animal’s size from a distance.
Wind Estimation with an MOA Reticle
MOA adjustment = [wind speed x (range / 100)] / constant
Constants vary by cartridge. For .308 Win, use a constant of 12. For 6.5 Creedmoor, use a constant of 17.
MOA adjustment = (range / 100) -1
The above formula is for a full-value 10 mph wind. Changes based on a wind direction are made after calculating your hold in MOA.
Wind Estimation with an MRAD Reticle
|Yards to Target||MRAD Adjustment (.308 Win)||MRAD Adjustment (6.5 Creedmoor)|
The above pattern is fairly universal, but you may need to tweak an adjustment here or there. Your specific rifle and ammunition will have a certain wind speed at which you can use this formula.
If you shoot a “6 mph gun” in a full-value 6 mph right-to-left wind, you would hold 0.5 mils right at 500 yards. If the same wind were a half value, your hold would be 0.25 mils. If the wind were full value but 3 mph, your hold would be 0.25 mils.