Re: What MOA rail should i get?
Depends on the load, and the scope. I have to get a bit technical to answer your question here, so bear with me.
There are two angular components to a short-range - say, 100 yard - zero.
One is compensation for the height of the scope over the bore. That angle may be computed as:
angle = arctan (height above bore / distance to target)
In the case of my AI, for example, with a height above bore of 1.75 inches, at 100 yards (3600 inches) it's:
angle = arctan(1.75 / 3600) = .03 degrees or 1.67 MOA
The other component is the drop from the muzzle to the zero range. With my load at 100 yards, that's about 2.7 inches, or, using the same formula above, about 2.58 MOA.
Add those two up, and it's about 4.25 MOA or about 1.25 mil.
Which is probably more than anyone really wanted to know. But that's the amount of elevation which is consumed by a short range zero, which the interested readers, if there are any, can compute for their own setup.
So, if I have a flat base on that rifle, I'd need at least 45 MOA of "up" elevation to get to 1000 yards, which means the total elevation in the scope at least 90 MOA.
Most scopes don't have 90 MOA.
But if I have a 20 MOA base, that takes means I start with 20 MOA of slant, so I only need 25 MOA of "up" elevation to get to 1000 yards, so I can do with a scope which has, say 60 MOA total elevation adjustment, which is the spec of all of the Leupold Extreme Range tactical line.