Everyone's eyes are different. Some folks just see better than others. A 4x is enough for those with good vision at 500yd for any big game animal...a 3-9 adds more capability for those that don't.
With that in mind, although the 6500 is a fine scope it is heavy, pricey and a lot more mag than necessary for 500yds. A nice scope for a dual purpose rifle that might challenge smaller targets, but a 7mm doesn't fit that exactly, and it's a bit much for a sporter rifle IMO, but if you want optics capable to twice that range then it is a viable option.
Same could be said of the 7mag...it's more than necessary. At 500yd, a 708 would do about the same work with the same bullet. It really just depends on the type of rifle you like to hunt with. If you like a heavier rifle with more recoil then go big 7, but the bullet is the more important choice these days.
TC
