I usually go 3 inches or 4 inches. But I make a complete square around the first shot. In other words three inches left and up for the first shot. Then 6 inches to right. Then 6 inches down. Then siz more inches back left. The up 3 inches and right 3 inches. This should return you to your very first point of impact(center dot) if your scope tracks perfectly.

Then take a ruler and measure your box. See how close it is to the measurements it should be.

This is strictly a one shot deal. Not shooting for a group. You want to know exactly how much your sope moves when you turn the turrets.

You will be suprised. But very few scopes will pass this test. Most Leupold's(of old) will not pass this test.

But some other scopes will really leave you amazed at how bad they work!!

As stated above I have a CDS on the new VX-3 and it works well. It also works well on my Swarovski 6X18, as well as my NF 3-15. Tom.