Riflescopes: MOA vs MIL
Whether you’re buying your first riflescope or your tenth, choosing a unit of measurement for adjustment is going to be a key factor in your decision. While there are valid reasons to choose either of the two most popular units, the most important decision to make is which you are comfortable with. Outdoorsmans recently attended a Leupold shooting school that was taught by an ex-Navy Corpsman that quite literally lives at their private shooting range. We went through three days of training and when we covered this topic, his advice that stuck with me is that it doesn’t matter.
Now, it does matter, but the point that the instructor was trying to make is the one we would like to convey to you. The best unit of adjustment is the one that helps you get a shot on target in the most efficient way. If you’re starting from square one, feel free to call us and we can walk you through the finer points of choosing between the two. For now, we’ll give you the crash-course on both, along with some questions to ask yourself to figure it out.
Mil (Milliradian): Unit of measurement of an angle within a circle.
MOA (Minute of angle): Unit of measurement of an angle within a circle.
Still reading? So far we’re tied.
The differences between the two come down to the actual math required for measurement. Contrary to popular belief, these units are not limited to imperial and metric. MOA measurement works cohesively with inches and yards, but a little math can make conversions for you. Mils work the same way and can be adapted to either system.
The supposed simplicity of MOA is derived from a slight mathematical cheat. This is so prevalent that it is printed on millions of riflescopes. One minute of angle is effectively equal to one inch at 100 yards, two inches at 200 yards, and so on. This is generally correct in practice, but one true minute of angle is actually equal to 1.047” at 100 yards. If you’ve ever used an MOA scope, you may have noticed the words “1 click = ¼ MOA @ 100yd” or “1 click=¼” at 100 yd” etched into the turret cap. This means that if you are an inch high at 100 yards, you need to adjust four clicks down to correct it. At that range, the extra .047” is not enough to make a significant difference for most shooters. The simple way to avoid any trouble is to use a ballistic calculator app or a rangefinder like a Leica Rangemaster 2800.com with ballistic “dial-to” capability.
The mil system does not come with a nice, round figure for calculations. One mil is equal to 3.6” at 100 yards. Since most mil turrets are in .1 mil increments, this means that if you’re 3.6” high, you would need to adjust down by 10 clicks. Using mil-dots or hash marks for holdover works in the same way. The large hashes or dots will represent one full mil of adjustment, usually coupled with ¼ or ⅕ marks in between for holdover. We generally advise using ballistic turrets, but for more info on first focal plane reticles and holdover, view our article on the subject here. (link)
Again, modern shooters are fortunate to not typically have to do mental calculations for adjustment. Using a ballistic rangefinder or smartphone app, you can enter your rifle’s data and get instant values for adjustment using either system. The process is now as simple as “range, dial, shoot.” In some cases, such as with the Swarovski dS, it is as simple as “range, shoot.”
This goes to further our point about preference. Modern equipment makes it so easy to get the correct values that the most important factor is comfort. You have to do math either way, so you’re basically choosing which math you will do. If your spotting scope can judge distance using one system, it is a good idea to match the system in your riflescope. Similarly, if you already own riflescopes that use either of these systems, we strongly recommend using the same units across all of your rifles.
If you need help with ANY riflescope related decisions, feel free to give us a call at 1-800-291-8065. We love talking scopes and rifles.