MilDots, MOAs, and BDCs, Oh My!

[Wap wap]

Make sure the eye relief (sometimes called the eyebox) on the Acog is something you can live with, its a bit tighter than some folks like.

whether you use mil or moa doesn't matter, knowing how much your load drops in the one you choose is what matters.

Most trained action shooters have the clock in the back of their minds, and this plays a bigger role in the choice of things than non-timed event shooters, thus different opinions on scopes. This also causes the mix to be different at different events, such as a F-Class shoot where there may be nothing but BR NF or in contrast a 3 gun where you'll probably see just about anything.

[Bigpops]

Wap Wap - if you live anywhere near Maryland I sure would love to sit down with you and pick your brain. It sounds like you have forgotten more about scopes than I will ever know.

[Wap wap]

Thanks for the invite,but I live in the west and thus get to try a lot of long range stuff not available to most shooters. I would be glad to point in a direction, offer from experience, or answer a question.

[Wap wap]

Might add that I haven't shot action pistol formally for a while. Started when I lived in Colorado, shot with Ross Seyfreid, Paul Miller, 3 gun with Jimmy Clark back when the matchs were in the infancy.

[Wap wap]

Back when Don Fisher in Denver was making and building 9 major guns on Browning Hi-Powers and I mean real major.

[Wap wap]

Back when --OK, OK.

[FB3GDQ]

Here is another scope to take a look at. The Horus scope was on the gun that won the sniper competition at Benning. This is a really good reticule for milling and long rang shooting. The scope is a ffp scope and matched up with the A-Trag ballistic soft ware this system is hard to beat.

http://www.horusvision.com/falcon.php

[Wap wap]

Horus is a good reticle and can be had in a USO, and I think NF now. Realize it adds about $500 to the basic scope cost however.

[Bigpops]

Here is another scope to take a look at. The Horus scope was on the gun that won the sniper competition at Benning. This is a really good reticule for milling and long rang shooting. The scope is a ffp scope and matched up with the A-Trag ballistic soft ware this system is hard to beat.

http://www.horusvision.com/falcon.php

I have read about these and I believe JP sells them and highly recommends them. They seem pretty cluttered to me but I am curious what you seasoned guys think?

[FB3GDQ]

Here is another scope to take a look at. The Horus scope was on the gun that won the sniper competition at Benning. This is a really good reticule for milling and long rang shooting. The scope is a ffp scope and matched up with the A-Trag ballistic soft ware this system is hard to beat.

http://www.horusvision.com/falcon.php

I have read about these and I believe JP sells them and highly recommends them. They seem pretty cluttered to me but I am curious what you seasoned guys think?

Well some of the seasoned guys are going to say the same thing you think that it is cluttered. If you shot with it on the range for a day most people who thought it was cluttered love them by the end of the day.

[Wap wap]

I have used one for a couple of days, but don't feel the additional cost is warranted. The ebr-2 reticle I use on a Razor works the same way and costs much less. Tactical matches are very much different than most long range shooting. Many things are "measured". Civilians shouldn't confuse their needs for what the military or LE are doing, or use it as a yardstick for measuring performance. Usually civilians come up with better solutions, simply because the constraints are there.

[h2osport]

My newest scope has 40moa below and above center cross hair for a total of 80 moa with out clicking.

Make and model?

U.S. Optics SN-3 3.8-22x58 FFP with PCMOA reticle. Cannot get full 40moa up and down on 22 power.

http://www.usoptics.com/get_image.php?uid=RET-050

Randy

[Graham Smith]

I have read about these and I believe JP sells them and highly recommends them. They seem pretty cluttered to me but I am curious what you seasoned guys think?

This is a classic case of suitability to purpose. For example, if I am shooting my AR at 8" steel targets anywhere up to about 225 yds, then I'm going to be able to hit them with nothing fancier than a $200 red dot sight. I know that because I know that the ballistic trajectory is within plus or minus X inches with my load and my zero.

If you decrease the size of the target to 6", then I'm going to start having some trouble past a certain distance because my eyes are not that good. So for that I'll probably want something with a little magnification. I still don't need anything fancier than a $300 scope in the 2x or 3x range with a simple dot or crosshair (or both) because all I need to do is just see it better so that I can be a bit more careful about aiming dead center of the target.

Once you get beyond 225yds or decrease the size of that 225yd target to that of a tangerine (read my post about my adventures shooting my AR in a sniper course), then two problems develop. First, I need some magnification to see better and second I need to be much more aware of the ballistic path because I'm going to be dead on at 200yds (my zero) but at 225, there will be a slight drop that I need to compensate for. And if the target is at 300yds, then I am going to have to hold over to compensate for even more drop. And so on. Once I'm out to 600yds with my AR shooting 69gr SMK @ 2900fps, then I have to compensate for about a 94" drop - basically at that point, I'm lobbing the bullets at the target like you would with a cannon - and it's in the 200 - 600 yd range where BDC (ballistic drop curve) reticles have an advantage.

From this point on, I'm relying on what I have read and my growing understanding of optics. Please don't take this a gospel because I could be (and probably am) wrong about some of this, but I find that a good way to learn is to explain things to others and have them correct you. At least, that's what I used to tell my students when I used to teach

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A BDC reticle has the ballistic drop trajectory built in. It's calibrated to a specific bullet and speed so that the hash marks correspond to hold overs at specific distances. Some scopes also have a separate set of marks that are used for ranging (determining the distance of the target to know which holdover to use). Once you get familiar with them with your gun and your load, they can be incredibly fast to use.

With a "regular" scope, if I know the distance to a target and know my ballistic curve, then I can look at my range card and it will tell me how much to adjust my scope. If I have a scope that has 1/4 MOA turret increments, then each click will move the bullet 1/4 of a Minute of Angle which is approximately 0.25" at 100yds or 0.5" at 200yds or 0.75" at 300yds, etc. If I have a scope that has 0.1 Mil increments then each click will move the bullet 0.1 of a Milliradian, which is approximately 0.36" at 100yds or 0.72" at 200yds, etc. Now, in either of these two cases, the actual type of reticle doesn't matter - it can still be a simple cross hair or dot. I'm changing the position of the reticle inside the scope so that when the crosshairs are on the target, that's where the bullet will hit. The advantage of this is that you can be more precise than a BDC reticle is because with it, you have to approximate the in between distances. The disadvantage is that it takes time to consult your range card and dial in the distance and even more time to adjust to shoot another target at a different distance. So, while dialing in the correction is more precise, using hold-overs or a BDC is faster.

After this, it starts to get a bit voodoo and I start to get a bit lost. First a bit about "focal plane" - this refers to where the reticle is actually positioned in the scope. Most scopes have the reticle in the second focal plane, that is after the image is magnified. As a result, in a variable power scope, as the magnification is changed, the reticle stays the same size. This makes it much easier to see the reticle since it doesn't get bigger or smaller as you adjust the magnification. The down side is that this makes hold overs more complicated. Imagine you are looking at a target that is 8" in diameter with a scope set for 4x and at a distance so that the target exactly fits between two hash marks. Now crank up the magnification to 10x and those same two hash marks now only bracket a small portion of the target. This is where I become completely lost with BDC reticles, I have no idea how you are supposed to use them when changing the magnification changes the "meaning" of the marks.

More expensive scopes are often first focal plane scopes. That is, the reticle is placed before the magnification takes place so that as you increase or decrease the magnification, the size of the reticle increases and decreases with the size of what you are looking at. This can be disconcerting but it has the advantage of keeping the reticle the same size relative to the object you are looking at. IOW, the above 8" target will remain fixed between the same two hash marks regardless of magnification. So if the third hash mark is the holdover for 300yds then it will remain so at 4x or 14x.

MilDot reticles are designed to take advantage of the fact that you can look at an object of a known size (e.g. the average distance from the top a sedan to the ground is something like 60" I think). You can see how many Mils that is by counting dots (or hashmarks) and calculate the distance. On a SPF (second focal plane) scope, this will only work at a specific magnification because of the issue mentioned above. On a FFP (first focal plane) scope, you can use any magnification you wish. This same principle used to be used on range finders like the old golfer range finder where you adjusted two lines to bracket the flag on the green and read out the distance. Now everything is electronic and lasers are far more accurate than anything you can do with a Mildot. You can also use a Mildot reticle like a BDC. All it takes is some calculating and some range time and you can create your own holdover table.

At this point, there is some gray stuff starting to leak out of my ears so I better stop while I'm ahead. If someone want's to pick this up where I left off and fill in the blanks, I'd appreciate it.

[Wap wap]

Nice glass!! optional reticle wasn't too much additional either. How is milling with the small distance between the has marks? what you using it on looks like you could use hold over to 2000 yds.

[Bigpops]

Thank you very much Graham. What I mostly got from your write up is...break out the wallet!

Seriously, nice write up. As I stated before a friend of mine just purchased a JP/Night Force combo. I shot his new gun this past weekend and was truly impressed. He is still figuring out the scope and all the terminology but the gun/scope combo is a true tack driver. I was impressed with the clarity and the recticle was easy to use and understand. Keep in mind we did not go past 100 yards though as he was simply breaking the gun in.

One thing that still has me partially baffled is parrelex.(sp) The NF had an adjustment for it and we used it to regain clarity. But what is it really doing? How is this adjustment different from first focal plane and second focal plane scopes?

[Graham Smith]

What I mostly got from your write up is...break out the wallet! <snip>

One thing that still has me partially baffled is parrelex.(sp)

Parallax

Common wisdom is to be ready to spend as much or more for a scope as you do for the rifle it's going on. But I am finding that this doesn't necessarily have to follow. I've been picking up a lot of good info at SniperCentral.com and while a lot of these guys swear by $1500+ scopes, a surprising number of them are quick to recommend scopes that are under $800 and even some that are under $400. Case in point, two frequently mentioned "quality budget scopes" are Wotac (Wonders Optics) and the Falcon Menace scopes. The Wotac 4-14x50 is a SFP scope built to the specifications of the business owner and the Falcon Menace 4-14x44 is a FFP scope built in England. Both are under $400. The fellow who runs SniperCentral is also a big fan of some rather inexpensive scopes from Burris and Bushnell. In fact the Bushnell 3200 10x40 has a street price of around $200 and this is the entry level scope he puts on the custom rifle package he builds.

Also, the Vortex Viper PST scopes are getting very good reviews and sells for about $600 for the 2.5-10x44 SFP scope with an illuminated reticle.

Edited October 27, 2010 by Graham Smith

[Wap wap]

whooh--were to start--

A 500 yd A zone is not a hard shot, a 500 yd head shot is not a hard shot, a 500 yd golf ball is a hell of shot.

It is not needed to use center of mass holds, that is action shooting talk, many top shooters use sfp scopes and fine cross hairs simply because they can "bisect" the target better than an ffp. Also if you are using a lrf complicated reticles become less useful.

Reading parallax definitions will just give you a headache. Here is the need to know. In most cases parallax adjustment is not needed. Absolute tracking accuracy is essential. A SWFA 3x9 with no ao is a better scope than a leupold 3.5x10 with ao. My hunting rifle uses a z6 2.5x12x50 TDS on an Alaskan Ti in 280, and using 162 amax at 2900 fps can make first shot hits on any A zone out to 600 yds day in day out. This is a non critical application. I use a NF 8x32x56 BR with 1pnrr, 1/8" clicks and an AO you wouldn't believe on golf balls at 500 yds. This is a critical application (small changes make big differences). With the reticle in proper focus, with scopes having a variable power of 10 or higher, the image will not be in focus with the reticle. AO simply correct this. Parallax occurs because you are not behind the center of the optical axis of the scope, if you are then no parallax occurs regardless of the fuzzy sight picture.

Bullets have two trajectory, one on the way up one on the way down, the one on the way down is the important one and as mentioned earlier why Leupold,Swaro, Zeiss pay so much attention when designing BDC reticles using information based on the drops between 200 and 300 yds. As the bullet approaches the target it sees two pictures or circles a circle of entry in front of the target and a circle of departure after the target (the statistical dispersion of the rifle/load combination). The target size defines the tolerence allowable in these circles.

I use a Conquest 4x14 z800 on an R5 Remington. It has a moa grid at the top and when used with the holdovers/windage holdoffs is pretty fast. I use a Diavari 6x24x56 with the z1000 on a TRG 22 for really serious shit. The reticle is zeroed at 100 yds, 3.2 mil adjustment "activates" the reticle to a 500 yds zero, allowing the use of the reticle holdovers and holdoffs. If left at the 100 yds zero I can simply use dial in elevation and use the scope at a lower power from 6 to 12 depending on how much field of view I want. Sorry for the complicated example.

A common misconception is that dial in is more accurate than bdc. Yes and know. Actually a combination of the two is the most accurate. Ex. Use the BDC for the known hold off dial in the difference. This method is recommended by NF. I use a 3.5x15x50 NF on AR10T using this method with the npr2 reticle (my favorite action reticle) because it has 2 moa hash. I like this reticle because it floats in sight picture.

You have the description flipped as to the ranging using ffp and sfp. FFP the realtionship or subtension of the target to the reticle hashes stays the same through the power range. SFP however has a linear relationship at decreases of mag. the more area subtended. This is were most folks get lost. Ranging with sfp and bdc holdover are two different topics, don't confuse them. Unless you are a sophisticated user the bdc will only work on the highest power or designated by the maker. This is the biggest complaint against them. However it is not that hard to change. Here is the work around. Using a program such as JBM (free on the net and one of the best) run your loads ballistics. Then simply compare them at the range with your scope at the range, or a 100 yd distance using a yard stick. Generally speaking when using a sfp scope decreasing the power will raise the point of impact. The greater the magnification range the greater the effect. Using my NF 8x32 I can walk the shot into the target by simply changing the magnification.

When using an ffp scope for holdover simply run a JBM sheet. The mil or moa drop from the sheet will tell you which mil or moa hash works for that yardage. (if yardage is a word, is meterage?) sorry for the long winded post.

[Wap wap]

A 2k scope on something like a $900 Savage will get you a lot further, than a $400 bushnell on a 2k Kimber 8400. Better yet a 3x9 ffp swfa on a $900 Savage with their new stock will get you 90% of anything you want to do and still leave 1k for doughnets.

[Bigpops]

Thanks again all. let me do some more reading before I ask anymore questions.

[Graham Smith]

Better yet a 3x9 ffp swfa on a $900 Savage with their new stock will get you 90% of anything you want to do and still leave 1k for doughnets.

I have seen 3-9x and 4-10x mentioned many times as being an extremely versatile power range. Right now, I have an inexpensive Leupold Mark 2 4-12x and at 600yds the 12x almost seems like more than I really needed when shooting at USPSA targets. But, again, it all seems to come down to purpose. That same 12x probably wouldn't cut it if it was a prairie dog at 600yds.

So many variables... <sigh>

[h2osport]

Nice glass!! optional reticle wasn't too much additional either. How is milling with the small distance between the has marks? what you using it on looks like you could use hold over to 2000 yds.

Nice glass is addictive! If you are not wanting to spend bucks on great glass, do not ever talk yourself into trying it. You will never be able to buy anything but the good stuff.

I do not range with my reticle although it is easy enough with the 2moa/10moa has marks. I use a Swarovski laser range finder. Have used it to range trees out to 1600 yards. Longest animal I have ranged was an elk at 840yds, but have not tried it on animals any farther out. Not always practical depending on surroundings, but it works for my area, and for what I am doing.

Scope is currently mounted on a AR-10 in 308. Not needing any holdover beyond 1400yds at the moment. If I need any farther than that, I will probably move it over to the 300winmag. Currently running a Nightforce 8-32X56 on it with NP-R2 reticle. Only 30moa of holdover on the NP-R2, so I would have to play with my zero distance to get to 1400yds.

Randy

[427Cobra]

IMHO anybody who sticks with MOA\MOA is anal about values, I used to be that person, I needed to know that 1/4moa was 1/4 inch at 100 yards, its really not but close enough, 1 MOA at 100 yards is 1.047 inches, or like I said close enough, I have a NF 5.5-22x50 NPR1 on my 308(MOA\MOA), on my 260 I put a Premier Reticle 5-25 Gen2 xr with .1mrad knobs(MIL\MIL), MILs is a dead simple system, no values needed, 1 MIL is 1\1000 of any unit of measurement you would like to give it, and .1mrad is 1\10000 of any unit of measurement you want to use, 1 light year at 1000 light years and so on, don't get anal and try to assign a value to MILs and you'll have the fastest and easiest system for making fast shots at any distance. Another plus for MILs is every single scope manufacture makes MRAD(MilDot) scopes, but not all of them have MRAD knobs, on the MOA side of things no two companies reticles are the same, some are IPHYs, TMOA, SMOA, you don't know until you box test your scope to know for sure what you got. I am a MRAD convert, I shoot in Practical Tactical(Sniper) matches where little time is given and goofy positions are the norm, MRADs simply work better for this, my 1000 yard DOPE is 8.2 MILs for my 260, on my 308 its 35.5 MOA, both those depend on conditions, but 8.2 is easier to dial than 35.5, 8.2 is also easier to hold than 35.5. My last piece of advice is DO NOT COUNT CLICKS, simply dope it, dial it, and send it!

Edited January 2, 2011 by 427Cobra

[Ken Kwiat]

A couple of other sources to check to help answer some of these questions.

Zak Smith's primer articles on LR Tactical competitive shooting. Zak's DemiGod site

And, of course, SnipersHide. It's where all of these issues are examined frontwards and backwards. Would recommend you read many of the sticky threads. Like Cobra elluded, basically the Sniper community is generally moving toward a pretty standard recipe for scopes, reticles, etc. Sure, there are plenty of personal preferences still (MOA vs. Mil? -- not a big deal as long as the turrets match the reticle). I personally like FFP scopes, with Mil/Mil setups. I currently use a Premier 3-15 with the Gen2 XR reticle on a AIAW in .260. That scope will probably move to a .260 LRP (gas) soon, a S&B 3-20 wishlisted for the AI.

The whole LR community is awaiting the Vortex Viper PSTs as said earlier. They have the "right feature set", we'll see about the glass. The price point rocks.

But, there is a reason why there is a pecking order of optics for LR Tactical (Zeiss/Hensoldt, S&B, Premier, NF, USO). Btw: most LR Tac competitors that I know dial for drop, hold for wind. That's where having some references along the main horizontal cross comes into play (e.g., mil dot or similar like the Gen2 XR, S&B P4F, etc.).

[Erik S.]

Let me first disclose that I have not read EVERY post in this thread, but for your application, I would seriously consider the Nightforce NXS FFP with MLR reticle.

Any time you can pair your reticle scale with your turret scale, life will be much easier. Since most people talk MOA already, I'd suggest that and it's much easier to convert to inches (i.e. 10" at 1000yds = 1MOA, whereas 1mil would be 36"...what the heck? you ask )

If you can afford it, USO with EREK knobs in .5MOA clicks will get you out to 1000 in a hurry! Once you reach that line of glass, it's all good.

As far as the Horus reticle, I've never owned a scope with one, but (for the application it was designed for) it's an awesome ret. Saw a Hendsholt on SnipersHide a while back with a Horus in it and, let's just say it wasn't on the market for too long.

FWIW

[Miranda]

I'd like to think I can read

and I'd like to think I understand balistics

and I can't claim I am an accurate shooter...

so I have a lot to think about when I am putting holes in paper.

the reason for the search for "practical scopes for dummies"

is because there is a lot to combine to make a long distance shot

just seeing the target.

knowing what the sight picture means.

understanding and estimating range.

the above in relation to the balistics of the rifle and cartridge

being aware of possible parallax gets tossed in there

we dummies are looking for a minimum standard to meet

so that we have a place to begin to understand

the .... more advanced... reasoning.

believe me I am interested, and I often get lost in these threads.

miranda