MOA Question


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Im getting a picatinny rail for my rem 700P and heres my question, the rails come in 0,15,20,25 moa. I think this means the scope is slightly sloping down. So at 1000 yards a 20moa for example will be like 220 inches lower than the barrels line.

Which one would be the most reasonable for shooting out to 1000 yards, for a Nikon Monarch 6-24? Im not shure how much travel the scope is going to have.

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I'm assuming you're talking about the 300WM...yes?

Here's a drop chart showing the amount of drop a 175gr bullet at 3000fps will have out to 1000yds. This'll give you an idea how much adjustment you'd need. The other factor will be how much elevation adjustment your scope has. Ideally you want the cross hairs optically centered.....meaning centered between the up and down travel within the scope. The idea of a canted rail is to keep from bottoming out the adjustments, but I bet you already knew that.

For whatever reason I couldn't get the drop chart to show correctly....

There's about 295" of drop from a 100yd zero. If you went with the 20MOA base you'd still need about 85" of adjustment from your scope to be able to hold dead on at that distance. That translates to 8.5" of adjustment at 100yds. If your scope dosent have that much travel you won't reach 1000yds without holdover. I don't know the Nikon product line so I can't be of any help there. You need to know how much travel your scope has.

If I'm wrong on my numbers would someone please advise...

Putting a canted base on will hinder you at close ranges. If you intend to use this rig as a dedicated LR rifle than a 15-20MOA might make sense, but for a average range rifle I wouldn't recommend it.

FWIW I have a 0-MOA base on my 300WM and had no issues reaching 600yds with a Leupold 8.5X25 LRT scope I still had plenty of adjustment left........BUT my cross hairs aren't optically centered.

hangunnr

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If I am correct the 34 MOA adjustment is the total distance the cross-hairs could adjust which would work out to 17" up or down from center at 100 yards. If my understanding of what hangunner is saying is right then you would have 170" of adjustment at 1000 yards with your scope on a flat rail. So then you need at least another 125" without having to hold over.

I think the 15 MOA rail would get you what you need. If you are going to be shooting that far all the time the 20 or 25 would be better. The 25 would get you close with little scope adjustment off of center and give you a clearer picture.

Haven't got a clue about ballistics out that far, but I am good with math.

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huntinguide,

Here's the chart I was trying to post up the other day.

175gr-.308 dia bullet at 3000fps with a 100yd zero.

chart.jpg

Pay attention to the Drop in MOA and the Drop in inches coulmn.

As you can see there is about -294.6" of drop at 1000 with this load. This translates to -28.1MOA. Now, If you have a mount that adds 20MOA which translates to 209.4", you will still need to account for the additional 85.2 inches of drop. If you break that 85.2" of drop down that translates to about 8.5" at 100yds. Assuming your scope has 1/4moa per click adjustments this'll mean you will have to come up about 34 clicks to hold dead on at 1000yds. Having a good quality scope with accurate adjustments for repeatable movements is crucial. This kind of adjustment is what seperates the men from the boys in the optics field.

Here's a link to a pretty good ballistics calculator. This one allows you to plug in different conditions that can effect bullet flight. I've used this and found the numbers to be pretty close.

http://www.eskimo.com/~jbm/calculations/traj/traj.html

hangunnr

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How are you gonna use the rifle the majority of the time? If it's gonna be a dedicated LR rifle then the canted base. As stated earlier this will hinder you at shorter ranges.

When I purchased the mount for my 300WM I went with a 0-MOA base. The Leupold I use has a very generous 90MOA of internal adjustment. I really didn't figure that I'd be shooting serious long range all that often so the flat base was in order.

It all breaks down to where you'll be spending the most of your time with the rifle....close to medium distance or way out there.

I know, I didn't directly answer your question.....:)

hangunnr

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How are you gonna use the rifle the majority of the time? If it's gonna be a dedicated LR rifle then the canted base. As stated earlier this will hinder you at shorter ranges.

When I purchased the mount for my 300WM I went with a 0-MOA base. The Leupold I use has a very generous 90MOA of internal adjustment. I really didn't figure that I'd be shooting serious long range all that often so the flat base was in order.

It all breaks down to where you'll be spending the most of your time with the rifle....close to medium distance or way out there.

I know I didn't directly answer your question.....:)

hangunnr

So was my answer anywhere close to right on that hangunnr?

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