I'd prefer 6x as the minimum, though it could be done at lower. If it was only going to be used for targets (maybe occasional hunting) and you weren't focused on "best" glass, I'd prefer a 10x SWFA if most of the time shooting was going to be at distance. The 10x SWFA is (IMO), the best back for the $ on a recreational target scope.
I use the NX8 1-8 and NXS 2.5-10's on several rifles. The 1-8 can be used at distance, but the reticle isn't designed for pinpoint accuracy there...it's designed for on target hits, but not fine work.
The NXS 2.5-10 will work very well at distance, and the ability to adjust parallax for on target resolution with it is great...but it will need to be used at 10x for reticle references.
