It depends on the size of the targets. Clay pigeons not very far......boxcars a looong ways.
Seriously, it depends on the quality of the glass/scope, the resolution of the scope and the conditions. It will also depend on the size of the target.
I've shot a lot playing around at 1000 yards with Nightforce scopes at 5.5 power but I can't do that with my Leupolds. Typically I will use as much power as I can for the given conditions unless I need the field of view for tracking the target.
If it's a quality scope then you should be o.k. at 1000 yards, or more, on moa sized targets.