NP-2DD reticle (12-42x56) and NP-R1 reticle (8-32x56). Either of these, or the NP-R2 listed by cdparker above will work for F-Class. The main difference is that the NP-2DD uses an aiming dot, rather than crosshairs. Because of this it is somewhat less useful for estimating corrections compared to the NP-R1 and NP-R2, which are hashmarked crosshair reticles. A lot is personal preference, so you might take a look at Nighforce's reticle descriptions page. Personally, I'm not too sure about the open aiming center of the MOAR reticle for F-Class. I'd probably need to look through one before deciding whether it would work for my eyes. The rest of it is very similar to the NP-R1/2 reticles.