I made a spreadsheet back in the dimly lit past to figure that out. You gotta subtract the front bell and add the eye relief--so you will get two results as the ER varies from low to high.
A besser answer is the 3-9x40 and bestest the 3.5-10x42
to answer your question: based on low power the 1.75-6 and based on high power, the 2-7
