Of Mils and MOA. Which turret suits you? (07.27.09)
We live in a wonderful time of choice when it comes to rifle optics. More and more models are hitting the shelves with features geared towards tactical shooters. This can be daunting for new shooters who are trying to make an educated choice. Today I am going to explain the two main turret options.
MOA Defined. MOA is an acronym for "Minute of Angle". This is an angular measure. There are 60 minutes to a degree and 21,600 minutes to a complete circle. Now that I have told you that, you can purge it from your memory because it really doesn't matter to us. What does matter to us, is that at 100 yards a "Minute of Angle" equals 1.047 inches. At 200 it equals 2.094". At 300 it's 3.141" and so on. Simply multiply 1.047 times the range in hundreds of yards.
MILs Defined. Mil is short for milliradian. There are 6,283.19 milliradians to a circle. One mil equals ten centimeters at 100 meters. This is where the confusion frequently starts. There is nothing Metric about Milliradians. The angles just work so that it appears that way. One Mil equals 1 inch at 1000 inches, 1 yard at 1000 yards, 1mm at 100cm, etc. Notice it works with metric measurements as well as with the imperial system.
Applied to Turrets. The preference in tactical rifle scopes has been for 1/4 moa clicks. Some can be found in 1 moa, 1/2 moa and even 1/8 moa, but the majority are 1/4 moa. Previously you could only find milliradian adjustments on high end european scopes or custom built US scopes. Lately this trend has been changing Falcon Optics, IOR Valdata, and a couple others now offer a Mil option on thier scopes. Most offer 0.1 Mil increments which equate to .34 MOA or 1/3 MOA clicks.
Why Mil/Mil? The most asked question these days seems to be, "What is the advantage to Mil turrets and a matching Mil reticle?" Lets think about our normal shooting situation. You sight in on your target at 400 yards. You apply the fundamentals of marksmanship and fire your shot. You see the impact is 6" low. Now since you are 400 yards away divide 6" by 4. You end up with 1.5. Now you need to come up 1.5 MOA (approximate) so that's going to be six clicks on your 1/4 MOA scope. You dial in the correction and fire. Now you hit your target. That's not too bad. It's a little math, but nothing we can't do in our head without coming off the rifle.
Now lets consider that you are on the same 400 yard line and this time your shot hits low again with your other rifle. This scope is equipped with a Mildot reticle and 0.1 Mil turrets. You observed that the impact was .5 mil low. You reach up, dial five clicks up on your elevation. The next shot is dead on. This is convinient, but not earth shattering.
Now lets move away from the KD range and all of it's neat yard lines and paper targets. Lets imagine we are on a hill out in the middle of nowhere. About 660 yards away you have a torso sized steel plate. You estimate the range and dial in your dope. You make your wind call, breath, aim, stop, squeeze and followthrough. You see the slash of the round in the dirt in front of your target. In your reticle you can see that you were 1 mil low. You dial ten clicks up on your 0.1 mil turret and re-engage. This time you see the puff of the bullet disintigrating on the plate and then the satisfying "clank" echo back to you.
It was quick and easy. If you weren't using a mil reticle and mil turrets your math could have thrown you off if you weren't very close on your range estimation. If you got flustered because of a time limit your cognitive process could go to hell.
That's all well and good when you are shooting for fun, but what if you are part of a Marine Sniper team tasked to recon a weapons cache on the side of a mountain in some dirty corner of hell. Your LRF (laser rangefinder) died two days ago when you fell down the hill bouncing on your ruck and your map for this area sucks. You just moved into your FFP when targets of opportunity appear. You get a quick and dirty range estimate off of your guesstimate on how tall the targets are. You squeeze off your first round. Your spotter is watching the target trough his spotting scope. He sees the impact, calls out "point five mils up, point two mils right, send it!" without breaking position you dial in the correction, hold for wind and reduce the targets as fast as you can work the bolt. Your spotter did not have to do any math in his head, no worrying about anything other that "what you see is what you get". This is what our Marines currently get with the new Schmidt & Bender scopes and thier Mil turrets.
So are mil turrets right for you? If you shoot known distance paper targets, it really dosen't make much of a difference. If you have a reliable LRF or are dead perfect on your rangeestimation and a math whiz who never gets it wrong, then they will be of little benefit. If you are like the rest of us who can sometimes flub a rage estimate due to a moving target, mirage, weather, etc. and can sometimes goof up multiplication and division under stress then mil turrets with a mil reticle are a feature you should look for in your next scope.
So what about MOA/MOA and IPY/IPY? The benefits of the Mil/Mil system can also be gained with any matching reticle and turret system. The key is that YOU know how to use them. I prefer the Mil reticle and Mil turrets because I have been trained on and have the most experience estimating range with a Mil reticle.