I did the unthinkable and put a varmint scope on mine a 4x12x50 AO and shot the center out the small yellow stickers with the diamond in the center at 50 yards after I got it sighted in yesterday.

So yes they are tack drivers, and could be used for varmint rifle.

At the age of 18 when I joined the US Military I swore an oath to support and defend the Constitution of the United States against all enemies foreign and domestic, that oath did not end with my retirement.