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Elevation and Windage Adjustment

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    Posted: June/28/2012 at 23:15
Hello everybody,
would really appreciate if anyone could explain what does this mean?  Windage and Elevation Adjustment Range: 80 m.o.a. (windage and elevation) ?

Does 80 moa apply at 100 yards, which means 80" above the center at 100 yards?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sparky Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 00:37
When they say 80 MOA or what ever value that is the total range. And generally you are centered (Approximately centered assuming that everything is setup correctly.) at 100yds so with 80 MOA you will have 40 up and 40 down. Same concept applies for windage. And when they say windage and elevation adjustment range 80 MOA they are saying that both adjustments are the same.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RotoReuter_DM Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 00:37
It means 80" total at 100 yards but after zeroing. It will not be at the bottom end you will have to turn the knob up and count what you have left afterwards.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 01:21
assuming that the scope is zeroed at 100 yards, what would 80 moa adjustment mean to 200 yards and further?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 01:44
my above question is kind of open ended.  Let me rephrase it.
assuming the scope is centered and zeroed at 100 yards; thereby providing 40moa of elevation.  would this 40 moa adjustment be 80 moa at 200 yards and 120 moa at 300 yards and so forth?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8shots Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 03:04
No 40 MOA stands for 40 Minutes of Angle. So that would stay 40 MOA regardless of the distance, it is an angular measurement. It translates to roughly 40 inches at 100yds. It is not quite 80 inches at 200 yds etc because the 1 inch is not exact enough to calculate to longer distances accurately.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 09:01
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Minute of Angle (M.O.A.)
Defined loosely, one MOA equals 1" at 100 yards, 2" at 200 yards, 3" at 300 yards.  If your 5 shot group at 100 yards fits inside a 1" circle then your rifle can be said to shoot 1 MOA.  Likewise, if every shot goes into a 2" circle at 200 yards.  If you can shoot a 10" group at 500 yards it would be 2 MOA.

There are 360 degrees in a circle. Each degree can be broken down further into minutes. There are 60 minutes in a degree. Likewise, there are 60 seconds in a minute. Now, to figure out the distance subtended by 1 minute at any particular distance, we need merely to plug those two values into a simple trigonometric equation. The tangent function fits the bill nicely. Here's the equation:

tan(angle) = distance subtended/distance to the target
(units must be consistent--e.g., 1/36 of a yard [1"] divided by 100 yards)

Now, we know the angle (1 minute or 1/60 of a degree) and we know the distance to the target (100 yards), but we need to figure out the actual distance subtended at the target (i.e., is 1 MOA actually 1" @ 100 yards?). What we need to do is solve for "distance subtended." Here's our final equation:

tan(angle)*distance to the target = distance subtended

Make sure your calculator is in "degree" mode (as opposed to "radian" or "gradian") and type in 1/60 (for degrees) and hit the "tangent" button. Then multiply that by 100 yards. This should give you the distance (in yards) subtended at 100 yards. Multiply this by 36 to get inches. The answer should be:

1.047197580733"

This is just a hair over the commonly quoted "one inch."  At 1000 yards, this would be almost 10 1/2 inches.  It is just a coincidence that 1 MOA happens to be REALLY close to 1" at 100 yards.....quite convenient.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:01
do you guys mean that regardless of the distance, the 40 moa adjustment would produce no more than (roughly) 40" at any distance? If this is true then I can't shoot beyond 40 moa of bdc?

however this is what I think. since my scope has 1/4" clicks where it roughly = 1/4" @ 100yd then the scope has160 clicks of adjustment. Further, 1 click = 1/2" at 200 yd thus the 160 clicks would roughly = 80" of adjustment at 200 yd.

please correct me if I'm wrong.

My bottom line question is, whether this 40 moa of adjustment is sufficient to shoot 1000yds w/308, 150 grain bullet FMJBT.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:10
Quit thinking in inches.  I know it is hard not to, because that is how are minds like to think.  That is where you are having the problem.  MOA is not inches, it just so happens that at 100 yards 40 MOA is about the same as 40 inches.  But MOA is an angular unit of measurement.  

At 1000 yards 40 MOA would be near 400 inches.

A scope with a total of 80 MOA should work just fine to shoot to 1000 yards with a .308.  Your choice of a 150 grain bullet may cause you some issues, but it will probably work.  Using a heavier bullet like a 175 will give you much better results.  You will for sure need to have a 20 MOA base on your rifle to make it work though. 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:14
Also just because a scope has 80 moa a lot of people automatically think you will have 40 down and 40 up when zeroed.  That is almost never the case.  You may have 30 up and 50 down once zeroed or something totally different.  So do not plan on having exactly 40 up elevation. 

Lets say you have 30 up and 50 down once zeroed.  Now by adding a 20 moa base, it will give you 50 up and 30 down.  Which should be oddles to get a .308 to 1000 yards. 

In my experience a scope with a total elevation adjustment of 70 MOA or more with a 20 moa base is good for a .308 to 1000 yards.  Depending upon elevation, bullet choice, velocity and other factors you should need between 34 to 40 MOA up elevation to reach 1000 yards.

 What kind and model of scope do you have?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:30
Thanks for your detailed response.

It's a bushnell elite 6500, 4.5-30 & 50 mm with paralax adjustment 25yd - infinity.

The scope also has a 600 feet adjustment feature it's called 600 DOA. What it is basically is bdc for 600 yd.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:32
Typo "feet" it is yards
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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:35
Originally posted by KIMBER8400AT KIMBER8400AT wrote:

do you guys mean that regardless of the distance, the 40 moa adjustment would produce no more than (roughly) 40" at any distance? If this is true then I can't shoot beyond 40 moa of bdc?

however this is what I think. since my scope has 1/4" clicks where it roughly = 1/4" @ 100yd then the scope has160 clicks of adjustment. Further, 1 click = 1/2" at 200 yd thus the 160 clicks would roughly = 80" of adjustment at 200 yd.

please correct me if I'm wrong.

My bottom line question is, whether this 40 moa of adjustment is sufficient to shoot 1000yds w/308, 150 grain bullet FMJBT.

1 MOA is approximately one inch at 100 yards or two inches at 200, three inches at 300 yards, etc.

As for 1000 yard shooting, 150gr FMJ ammo is generally inadequate for it.  To reach that far out you need to step up to higher quality ammo that shoots a heavier bullet.

Generally, proper 308 ammo drops somewhere between 10 and 12 mils at 1000yards, which works out to be approximately 34 to 40 MOA depending on your specific rifle and ammo.

If your scope is set up correctly on a 20MOA base, you should have plenty of elevation available.  If you are using a 0MOA base, it will get pretty close.

For 1000yard shooting, I presume you are planning to go to Piru?  There are not a whole lot of ranges around SoCal that offer that distance.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:38
Originally posted by KIMBER8400AT KIMBER8400AT wrote:

Thanks for your detailed response.

It's a bushnell elite 6500, 4.5-30 & 50 mm with paralax adjustment 25yd - infinity.

The scope also has a 600 feet adjustment feature it's called 600 DOA. What it is basically is bdc for 600 yd.

Just saw this post.

Elite 6500 4.5-30x50 has 50MOA of adjustment range, so it will be a bit difficult to stretch it out to 1000 yards with a 308, though not impossible.  You will definitely need either a 20MOA base or some other means of elevation adjustment with a mount.

ILya
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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:42
Just be aware that the hold over reticle will only be calibrated for a specific magnification.  What it is on that model scope I am not sure.  Most scopes they are calibrated to work on the highest mag only.  So if you try to use it on a lower mag you POI will be way off what you think it will be.

They work just fine if you know how to properly use them and you practice a lot with them.  I use one on my 1.7-10x scope with a 300 wsm and I can make easy body sized hits to 5 and 600 yards without much trouble.  Mine is calibrated to work on 10x.  If I put it on 7x my POI would not be the same as on 10x.  So make sure you learn how to use it properly first. 

Also it is probably 600 yards not 600 feet.  That bottom hold over mark is suppose to mean your bullet will hit right on at 600 yards.  But for what caliber?  What elevation?  What velocity? Etc, etc.  WIth your caliber, bullet choice, elevation, etc,  that bottom line may be somthing like 530 yards or 650 yards.  It is hard to say.  So again you just need to practice and learn how it works. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 11:53
Originally posted by supertool73 supertool73 wrote:

Just be aware that the hold over reticle will only be calibrated for a specific magnification.  What it is on that model scope I am not sure.  Most scopes they are calibrated to work on the highest mag only.  So if you try to use it on a lower mag you POI will be way off what you think it will be.

They work just fine if you know how to properly use them and you practice a lot with them.  I use one on my 1.7-10x scope with a 300 wsm and I can make easy body sized hits to 5 and 600 yards without much trouble.  Mine is calibrated to work on 10x.  If I put it on 7x my POI would not be the same as on 10x.  So make sure you learn how to use it properly first. 

Also it is probably 600 yards not 600 feet.  That bottom hold over mark is suppose to mean your bullet will hit right on at 600 yards.  But for what caliber?  What elevation?  What velocity? Etc, etc.  WIth your caliber, bullet choice, elevation, etc,  that bottom line may be somthing like 530 yards or 650 yards.  It is hard to say.  So again you just need to practice and learn how it works. 

Bushnell's DOA 600 reticle is calibrated to work at 20x in the 4.5-20x50 scope.

It is designed for faster cartridges though and it is not going to work very well with 308Win.  It might fit with some tinkering (with both magnification and sight in), but I do not think Bushnell publishes the actual dimensions for the reticle, so I would need to do some measurements first.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 12:49
thanks for your responses fellas it's appreciated.

Just spoke w/bushnell rep was informed it only has 50 moa at 100yd. The store gsve me the wrong info 80 moa.

I have the 20 moa base so that will give me 70 moa.

I wonder if i could combine the 600doa reticle w/elev adjustment to reach 1000yd; provided that proper weght of ammo is used?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 13:09
20 MOA base does not add to your adjustment range.

It allows you to use more of the adjustment range your scope has.

For example, with a scope that has 50MOA of adjustment if the mount and gun fit each other perfectly and you are zeroed right in the center of the adjustment range, you have 25MOA of upward adjustment and 25 MOA of downward adjustment.

If you use a 20 MOA base, and everything else works out perfectly (which seldom happens), you will have 45MOA of upward adjustment and 5MOA of downward adjustment.

The total is still 50 MOA, but how much you have available fro trajectory compensation varies.

As for combining your reticle with the adjustment goes, while it may be theoretically possible, it would be difficult.  Your reticle was not designed with that in mind, so the hashmark spacing is likely to be suboptimal for it.

ILya
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Post Options Post Options   Thanks (0) Thanks(0)   Quote supertool73 Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 13:12
If I were you I would sell that scope anyway.  30x is way more than is needed for the kind of shooting you want to do.  If you get the 2.5-16x I believe it does infact have more MOA adjustments.  16x is about max for the elite optical quality anyway.  Sure you can add more, but your image quality will really start to decrease.  And 16x is great for up to 1000 yard shooting.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KIMBER8400AT Quote  Post ReplyReply Direct Link To This Post Posted: June/29/2012 at 17:00
thanks for all ur support fellas.
I'll go to the range and try the max 600 yd and if it works then i gotta find myself 1000yd range. If 600 yd doesn't work then ill sell it.
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