Mil vs MOA: Much of a Muchness
It’s 0500, I’ve just knocked off work and Mark from Tactical Optics SA calls me on my way home. Who the hell calls someone else at 0500 with serious technical questions? I’m not complaining though, it keeps me awake on the drive home.
Mark drops a loaded question: what do I use, Mil or MOA, and why?
Mil or MOA is one of those questions that gets everyone’s knickers in a knot, and divides shooters like Moses parting the Red Sea. It’s a polarising question, and understandably so. We are all comfortable with what we know, and change is unwelcome.
Mil became popular in the early to mid 2000s with tactical/precision shooters, due in no small part their exposure to the growing popularity of Mil scopes within the military. In truth, the US Marine Corps were using Mils way back in the 70s, but civilian shooters really didn’t pick up on it till much later. There was a fair bit of “Mil guys are just wannabe snipers” going around. The fact of the matter is, Mil and MOA are just different ways of skinning the same cat, and while Mil is certainly more popular among military and tactical/precision rifle competitors, it doesn’t mean it is the better system.
Here are the basics. Mil is short for milliradian, which is an angular measurement. An angle of 1 radian is the angle where the length of an arc is equal to the radius of the circle. A milliradian is therefore one thousandth of a radian.
MOA is the acronym for Minute of Arc. Shooters tend to refer to it as Minute Of Angle. A MOA is an angular measurement that corresponds to one sixtieth of a degree.
So Mil and MOA are both angular measurements, what’s the big deal? Most shooters will qualify the “Mil or MOA?” question with “what are you more familiar with? Imperial or Metric measurements?” From here on out it devolves to “MOA is Imperial and Mil is Metric” or some variation of this tired old myth.
Mil and MOA have nothing to do with the Metric or Imperial system of measurement, period. Mil and MOA are angular measurements that can be applied to any unit of measurement. It just so happens that Mil works perfectly with Metric and MOA works close enough with Imperial. Using the Imperial system, one MOA is 1.047 inches at 100 yards. One MOA is 10.47 inches at 1000 yards. Using the Metric system, one Mil is one centimeter at 100 meters. One Mil is one meter at 1000 meters. The Metric system is a better fit for Mil than Imperial, as it is base 10, whereas the Imperial system is a “close enough” fit for MOA. Its no wonder people tend to think of Mil and MOA as Metric and Imperial, the reality is, they are not.
So which one should you use? The first question to ask is “what kind of shooting are you doing with this scope?”, followed by “will the distances be set and known?”, followed by “how precise do your scope adjustments have to be?”, and finally “will you be shooting under stress?”. For shooters who are target shooting on a square range with no stress factors such as time limitations and/or improvised positions, at known distance targets, who want as precise scope adjustments as possible, then MOA is the way to go. For shooters who are on a two way range and receive return fire whilst engaging targets at an unknown distance, under a great deal of stress, and time is a significant factor, then Mil is the way to go. Ok so that doesn’t exactly describe the average sporting shooter, but military snipers use Mil because it is faster and more intuitive, especially under stress. More realistically, for shooters competing in Precision Rifle Series type events, where a lot of shooting is done in improvised positions, the targets are of potentially unknown sizes, at unknown or awkward distances, where fast follow up shots are required, and speed trumps absolute precision, then Mil is the way to go.
A lot of MOA shooters will disagree with me when I say MOA is slower to use and less intuitive, but hear me out and you might change your mind. MOA scopes may have reticles with mismatching vertical and horizontal graduations. In older scopes, the vertical graduations might be in 2 MOA increments, where the horizontal graduation might be in 5 MOA increments, or some combination thereof. Various riflescope manufacturers have since migrated to matching vertical and horizontal graduations. MOA scopes can have turrets that adjust in 1/2, 1/3, 1/4, and 1/8 MOA. Working a MOA scope with a reticle that has matching vertical and horizontal graduations, with a turret that adjusts in some weird fraction of a MOA, takes some getting used to. If you see that you’ve missed by 1.5 MOA to the right of the target, you have to dial 3 clicks left if your scope is adjusted in 1/2 MOA, or 5 clicks left if it adjusts in 1/3 MOA, and so on. It isn’t quite circle in a square hole, but it isn’t exactly intuitive.
Mil scopes tend to have reticles with matching vertical and horizontal graduation measurements. Everything is one Mil, or tenths of a Mil. Most Mil reticles these days have graduations marked at half a Mil, two tenths of a mil, and one Mil. All Mil scope turrets bar a few exceptions, adjust in 1/10 Mil. Adjusting for missed shot is far simpler with a Mil scope than with a MOA scope. 1.5 MOA is equal to 0.436 Mil. Using the same example as above, to adjust 0.436 Mil left you simply dial 4 clicks. No mucking around with quarters or eighths or thirds, just straight up tenths. As we can see, Mil is a coarser adjustment than 1/4 and 1/8 MOA, so keep that in mind.
Because Mil scopes are based on tenths of a Mil, most people find Mil scopes are faster and more intuitive to use. MOA scopes on the other hand have a variety of possible combinations. In terms of absolute precision of turret adjustments, MOA scopes can be more precise than Mil scopes, hence the question of the level of precision required. So which is right for you? Ask yourself those four questions above, and you should have a pretty clear answer. For me, the deciding question is stress factors. If there will be some kind of stress involved in your shooting, apply Occam’s Razor and use a Mil scope.
Regardless of if you choose Mil or MOA, make sure you buy a scope with a matching reticle and turrets. A matching reticle and turrets makes everything much easier. If you see you’ve missed by x Mil/MOA, you can dial x Mil/MOA on your turrets. What you see is what you adjust for. There are few things more frustrating for a shooter than to have to convert splash seen on a Mil reticle, to MOA turret adjustments or vice versa, on the fly. All things being equal a MOA shooter will have to work with larger numbers and dial more clicks to achieve the same elevation or windage adjustment than a Mil shooter, assuming the MOA scope adjusts in 1/4 or 1/8 MOA. For example, a typical 308 match load will require between 9.5 to 11.5 Mil elevation for a 1000m target. That translates to 32.7 MOA to 39.5 MOA. A Mil shooter will dial between 95 and 115 clicks whereas a MOA shooter will dial between 261 and 316 clicks with a scope that adjusts in 1/8 MOA, or between 131 and 158 clicks with a scope that adjusts in 1/4 MOA. Does that make an appreciable difference in real life? Personally I think it does, but I’ll leave it up to you to decide.
Now, the final consideration to make, which can completely change your final decision: will you be shooting with a spotter, and what would work best for the team? Exploring the shooter/spotter dynamic is beyond the scope of this article, however, I will say this: If your spotter is very well versed in Mil and you’re sitting on the fence, get a Mil scope so you can communicate better with your spotter. The same goes for if your spotter is very well versed in MOA. Choose whichever system is most applicable to the team. I’ll post up a separate article about shooter/spotter dynamics, and why the choice between Mil and MOA is critically important for a shooting team.
So what can we take away from all this? Mil and MOA are angular measurements. Choosing between the two boils down to application rather than personal preference. Mil is the easier of the two to learn and apply under field conditions and under stress. What do I use? Mil. Most of my shooting is done in the field, under some kind of time stress. My targets are irregularly sized and at awkward ranges, and absolute precision is second to speed. Based on these criteria, and the fact that no Chairborne Ranger would ever be caught dead shooting MOA (because that’s so 1980s, man), I’m a Mil guy through and through.