On Optics Planet w/ Mil-Dot (Mrad) Reticle $1099:
On Burris Website w/ MOA Reticle:
Riflescopes have come a long way in the last ten years. It used to be that only elite hunters paid big money for high quality scopes, and those scopes mostly came from Germany. I don’t know if patents ran out on manufacturing methods, or manufacturing just got that much better overseas, but these days there are a lot of great scopes that are crystal clear even in low light conditions, and they don’t cost big money. You can still spend over $5,000 on a riflescope, but for $1,000 to $2,000 you can get what I’ve found to be as good a scope for a lot less (and sometimes even less than $1,000). This Burris XTR II 4x-20x is made in Malaysia, and I would put it against scopes many times its cost.
More important to me, the XTR II is also one of my first experiences with a new generation of “first focal plane” or “front focal plane” inexpensive import scopes. If you have never shot with an FFP scope, they work basically the opposite of a “regular” riflescope. In a regular scope, the reticle (crosshairs or similar), stays the same size and the background zooms in and out. With an FFP scope the reticle zooms with the image and gets bigger and smaller as you zoom. See the pictures. The result is that the range estimation and holdovers for the scope are always the same.
Sounds confusing right? Well that’s because it is confusing, but if you boil out the individual parts, you’ll find that it isn’t as hard as it seems.
You may already have already tried both range estimation and holdover with your existing scope. But with a regular scope, those functions only work at a given power of the scope, usually the highest power. There are also scopes that are specifically tuned to your ammo, so your holdover at the very least is already delineated on the reticle. The most common of these are scopes that are specifically for .223 and for .308, and then there are also custom turret scopes, which are really the best if you want to keep things simple. Range estimation is not usually discussed with the very simple reticle scopes that come with hash marks for 100-1000 yards printed right into the scale.
Mil-Dot/Mrad vs. MOA
Not keeping things simple gives you the most flexibility, especially if you plan to use the same scope for different loads in the same rifle, or on different rifles. That is why the military, long distance hunters and most competitive shooters use a more general reticle with either the “mil-dot/Mrad” system, or the “MOA” system. Once you learn rules of how either system works, range estimation and holdover are easy. You have probably heard the term MOA, or “minutes of angle,” and mil-dot/Mrad, aren’t like that, so I’ll explain the difference.
MOA is figured in degrees of a circle. One “minute of angle” is 1/60th of one degree, A circle has 360 degrees in it (think of a compass), so one minute of angle spans a wedge coming out from the center of the circle measuring 1/60th of 1/360th, which is 1/21,600th (don’t worry you never use that number). One of those “minutes of angle,” coincidentally and conveniently, equals 1.047 inches at 100 yards. So when we say that a rifle shoots into one “minute of angle, it usually means that when you take a number of shots, usually 3 to 5, absent human error, all of the bullets fall within that inch. Likewise, when you click your scope that is labelled “1 click = 1/4MOA,” that means that each click will move your point of impact about 1/4 of an inch at 100 yards.
Mil-dots, or Mrads, are a different type of measurement based on “radians.” A radian is likewise a way to split up a circle, and I won’t get into the math involved, but a “mil” or “Mrad” is 1/1000th of a radian. One mil equals 3.438 minutes of angle, or 3.6 inches at 100 yards. So, since a mil/Mrad is much courser of a measurement than one MOA, generally mil/Mrad scopes are clicked in 1/10 mil/Mrad increments, or .36 inches at 100 yards as opposed to .25 inches for an MOA scope.
Don’t stop reading now if you got this far. Estimating distance does require that you re-organize your brain a little bit in the way you think about your scope, but with a first focal plane scope it makes a lot more sense than with a regular scope. As you can see from the pictures, the dots on a mil-dot/Mrad scope and the lines on an MOA scope get smaller and bigger in an FFP scope, so they stay the same size relative to their surroundings. Whether you are at 4x on the XTR II or 20x, the height of a man at a given distance is going to be the same amount of dots or lines tall. Since you can see him in your scope, and estimate his height at say 6 feet, your scope can tell you exactly how far he is away.
On an MOA scope, you multiply inches times 100, divided by MOAs. That equals yards away. So say the guy is 6 feet, which is 72 inches, you divide 7200 by how many lines tall he is in the scope, call it 8 MOA. That equals 900 yards.
A mil-dot/Mrad scope is the same type of methodology, but it isn’t inch/yard specific. You can use it for meters also. The formula is yards or meters in height of the object, times 1,000, divided by mils/Mrads. So for the same 6 foot guy, you could say he is two yards high, times 1,000 equals 2,000, divided by 2.33 mil/Mrad (the same 8MOA when 1 MOA = .29 mil/Mrad) equals 858 yards. The same system can be used for yards to yards or meters to meters. If you estimate an AR mag well at 2.5″ wide through your scope is .5 mil. That is .069 yards (2.5/36), times 1,000 divided by .5 mil is 138 yards. Once you get it, you get it, but read it a few times and Google other ways people explain it and eventually it will sink in.
The MOA estimation is not as precise as that computed by mils/Mrad because of the 1.047 inches, not 1 inch, at 100 yards. Mils/Mrads is almost universally the preference of competition shooters and military snipers for this reason. But in recent years, with a new appreciation for high quality optics in the American shooting market, the MOA scopes have become more popular, probably because few people ever actually learn the math and we hear MOA, MOA, MOA so often in industry marketing materials. I prefer mil/Mrad scopes.
Once you know your distance, any ballistics calculator will give you the holdover. I use a free calculator on my Android phone called Strelok, and I paid for a great one called Shooter. There are hundreds of others in the Play store, and several scope companies have their own app, but not Burris (Strelok has Burris reticles). I like using the non-branded apps much better, and Shooter now has a plugin to connect Kestrel weather products right to your phone.
If you have never used a ballistics calculator, check out this very basic one at Hornady. As you can see, figuring your downrange point of impact comes down to several factors that interplay with each other. The first is velocity at the muzzle. This can usually be found on your box of ammo, but note that this velocity is calculated with a certain length barrel, 24″ for a bolt gun generally. If you aren’t using a specific brand of ammo with a known velocity, or your barrel length is shorter, you may have to guestimate, or ideally buy yourself a chronograph for about $100. Your bullet itself also has a specific value that is very important, called “ballistic coefficient.” The higher the number, the easier the bullet flies through air, and either your ammo maker or if you reload, your bullet maker, will have the “BC” of the bullet listed on their website. The weight of the bullet is the third factor, and this is a factor that also figures into the BC, because a heavier weight, less pointy, bullet will have a higher BC than a light pointy bullet. Leaving any of these factors out of your ballistic calculator, or guessing at them, won’t give you good results.
Once you plug in these factors and tell the calculator the height of your scope and your original sight in distance, it will spit out a ballistics chart of some kind for you to use as a “dope card” in the field, or you can just reference your phone. Advanced calculators like Strelok and Shooter will give you a lot of other factors, which are outside the scope of this article, but as you can see, estimating distance is crucial. If you have the ability to get a digital rangefinder, it is a great way to practice estimating with your reticle.
Holdover can be given in inches, mils/Mrads or MOAs. Ideally you will set your calculator to whatever you are using. The Strelok app gives you all of them, and it will show you in the reticle where to hold for your both your distance drop and horizontal windage, if you have any wind.
First Shot Hits
It may sound very precise to calculate all of these things, but even the most advanced and skilled snipers rarely make first shot hits at beyond 300 yards. As precise as the best sniper rifle can shoot, and as good as these numbers may sound, rarely do they all add up correctly. Air density, the spin of the earth, the slant angle of the shot, and a number of other factors can be calculated, but you’ll sit there all day and rarely does anyone do that comprehensively. Also, even a .5MOA rifle at 500 yards has 2.5 inches of spread from physical factors alone, so calculations for a head shot at that distance is still little more than a very educated guess, and a lot of luck.
First Focal Plane – Is it better?
If you Google reviews of FFP scopes, you’ll find that they don’t have a good reputation historically, because even though they make a lot more sense when it comes to calculations, the old scopes didn’t maintain zero along the range of magnification.
Therefore, for this article, I shot the Burris XTR II with a great rifle we got from TacticalRifles.net several years ago, to test just this issue.
First I shot a few base groups, and even with my moderate skills, at 20x this gun will shoot into .5 inches at 100 yards all day. Human error (mine) is the only reason you aren’t seeing a ragged hole that you can’t even measure, because the gun is just that good. My “secret weapon” in factory ammo is the Hornady American Whitetail 150 grain you see in the pictures. For some reason it shoots great in every .308 I have fired it in.
Then I shot the same load in the same rifle at the same distance for 7 rounds, one round each at 4x, 6x, 8x, 10x, 12x, 16x, and 20x. Now granted, I am going to have a lot more “human error” at 4x at 100 yards than at 20x, but I still was able to keep all 7 rounds consistently into under 1.5 MOA, and several groups were in the 1MOA range. I can’t shoot much better than 1 MOA at 4x at 100 yards, even in my Caldwell Lead Sled.
So as much as I could measure, this Buris XTR II FFP scope shoots into the same hole along its range of magnification, to within 1 MOA at the very worst, and probably much better. This is a trait that very few people measure in scopes, and I hope to try this with a bunch more regular and FFP scopes, because all other factors somewhat equal, this is really what separates a good scope from a great scope. I am a big fan of FFP scopes, and this Burris XTR II is a keeper. I hope they let us keep it.
If you follow GunsAmerica Digest, you may remember the article before Christmas I did on scoping your M1A. In that article I tried the sister FFP scope to this XTR II called the Burris Veracity. If you look in the pictures for the XTR II and the Veracity pictures, you’ll see that this XTR II is an open turret scope meant for competition and advanced sniper work, whereas the Veracity is capped turrets, and made for more of a hunting application or sniper work where most of your shots will be within easy holdover distances. Clicking a scope like the XTR II into correct holdover and windage is an art in itself, and really requires practice. Spending money on the scope itself may seem like the hard part when it costs upwards of a grand or more, but the really hard thing is to slow down and spend the time to know your rifle, learn your ballistics, and practice using your scope so that you are a deadly combination. I’ve become a big fan of Burris scopes, and I intend to be back for more of these in depth articles on just how to use them.