15 or 20 MOA base???

[HankePanky]

I'm currently kitting out my new 26" 300 win mag for long range (1000 yds.) shooting. The scope I'm looking at has 18 MIL (or 60.75 MOA) of total vertical adjustment. I'm wondering if I should get a 15 MOA base or 20 MOA base.

I would like to be able to have a 200 yard zero and still be able to track to 1000+ yards. Would the 20 MOA likely be too much for the 200 yd zero? Would the 15 MOA likely be not enough for 1000+?

I would appreciate any input.

 

[FEENIX]

I'm currently kitting out my new 26" 300 win mag for long range (1000 yds.) shooting. The scope I'm looking at has 18 MIL (or 60.75 MOA) of total vertical adjustment. I'm wondering if I should get a 15 MOA base or 20 MOA base.

I would like to be able to have a 200 yard zero and still be able to track to 1000+ yards. Would the 20 MOA likely be too much for the 200 yd zero? Would the 15 MOA likely be not enough for 1000+?

I would appreciate any input.

20 MOA is perfect!

 

[FEENIX]

20 MOA is perfect!

From an optics SME ...

Even though the scope adjustment range may be large enough to get to 1,000 yds, you should use a 20 moa base. That's because off-axis optical aberrations that degrade resolution increase with incidence angle. You should set up your rifle so that the incidence angle is minimized for long distance shots (where resolution matters most).

Assume the base is within +/-10 moa of alignment with the rifle bore. Let's also assume your bullet drops no more than 30 moa at 1,000 yds, and you like to zero your rifle at 100 yds. With a standard base, you would need up to -40 moa of adjustment to get to 1,000 yds. That means you need a total 80 moa of adjustment.

With a 20 moa base you would need up to -20 moa to get to 1,000 yds, but up to 26 moa to get to a 100 yd zero (worse case boresight alignment in each case). That means you need a total 52 moa of adjustment. With a 20 moa base, however, the incidence angle at 1,000 yds is 20 moa less, so the image will have less blur.

 

[HankePanky]

Thanks. I ended up getting a Leupold Mark 4, Long Range (20 MOA), steel base. So far, it looks like it'll get the job done.

 

[FEENIX]

Thanks. I ended up getting a Leupold Mark 4, Long Range (20 MOA), steel base. So far, it looks like it'll get the job done.

Yep, that should do it! If you have not done so already, you might want to consider ...

[ame]https://youtu.be/d6RopWI0-GE?t=4[/ame]