Scope should be FFP as courses of fire can be shot with hold over/under
Christmas tree style reticle
Dialable turrets are a must
MiL turrets and reticle are the standard
Zero stop
Parallax done to 25 yards
20 - 25 power magnification , mostly use 12 -18.
I agree lifetime warranty is useful
Check out scopes from Element, Athlon, vortex,Arken etc