Just looked at NF Catalog and didnt see a 40 mm Objective. I have a 3.5-15x50 NF, 5.5-22x56 NF and had a 8-32x56. Good quality scopes. A little more cost than a leupold and I believe the optics of the NF are better out past 1000 yards. If you really shop around the net you can find some pretty good deals on any of these scopes. IF you go with a NF try and get the NP-R1 reticle. It is a MOA reticle and will match your MOA turrets on the scope. The NF turret has 10 MOA per 1 complete rotation and the Mark 4 will give you 15 MOA per 1 Complete rotation. NF power ring when turned also moves the entire eyepiece so if your gonna use BC Caps you will need to position them in a manner to where you can still turn the power ring and not interfere with bolt operation on your weapon.
Hope this helps