Originally Posted by bruce_ventura
Does your scope have 35 MOA or +/- 35 MOA of adjustment? If its only 35 (+/- 17.5), then you will need to shim your base as well to get the 200 yd zero at a scope elevation of 0-2 MOA from the limit of adjustment (the extreme bullet down limit). This would require an accurate boresight collimator, or a lot of time shooting at the range. You should also reduce your ring separation to increase the elevation bias available from the Burris rings.
Thanks for all your feedback so far, guys.
The scope has a total of 35 MOA adjustment. The Burris ring set has the offset shims.
However I still don't have a full understanding of how a 20 MOA base or shims affect the impact point / reticle adjustment from 100 to 1000 yards. Furthermore there is the issue of adjusting a scope to its limits and the resulting effect on image quality.
So, let me understand. If I had a 20 MOA base OR installed 20 MOA ring shims on a set of high rings, and say the bullet drop at 100 yards is 2" @ 100, 8" @ 200 yards (similar to many calibers), wouldn't the impact point be too high even at the lowest reticle setting at 100? How many MOA from the bore line vs. sight line does that 2" or 8" bullet drop represent? (I supposed this is affected by the ring height - low med or high.) I bought a 0 MOA base (picatinny rail) because I was concerned I wouldn't be able to adjust down enough to zero at 100 or 200 if I used a 20 MOA base.
Next comes the issue of image quality when adjusting the reticle to extremes. If I do use a 20 MOA base or 20 MOA of ring offset shims, and then need to adjust the reticle down to 3 - 5 MOA from the scope's lowest setting for a 100 or 200 zero, how much image degradation will I incur? Much of my shooting is between 200 - 500 yards. Do I have to give up image quality for the ability to reach out to 1000 yards?
Up til now I have mostly used holdover to adjust for drop. The duplex post, or Nikon BDC. The Nikon BDC system has worked great for my most common conditions, but won't cut it for shooting over 700 yards. I've had a lot of fun chrono-ing my loads and programming them into the software, then seeing how that matches up to the physical reality of holdovers and impact points. Now I want to get into adjusting the reticle for distances.