The prostaff will get you started no problem. I have a 4-12x40 on my Abolt 7mm, and while i dont shoot at actual targets of for groups, ive had little problem resolving and hitting head size or larger rocks out past 400yds (limits of my RF on that size target), once I figure out the hold.
I also have 4 other prostaffs that are solid scopes.
One scope you may want to take a look at is the Bushnell Ultra HD 4.5-14x44.
Ive got one on my new .250AI, and while i havent shot it at range yet, Ive played with it enough to be of the opinion that at least in terms of optics it is, to my eye, superior to the prostaff line.
I have a smaller UltraHD on my .458 socom and its survived fine for a couple hundred rounds now, and that thing jostles you pretty good.
Another is the Primary Arms 4-14x44.
I dont own one, my brother in law has one that ive played with some, for budget optics I think these are quite good also.
The UltraHds made in china, and im not sure about the PA, if thats a concern.