Re: How much magnification is enough for 308 to 800?
10x will serve you well in just about any application. It blends the balance well between magnification, and field of view. In the summer time it won't have so much magnification as to make the mirage unmanageable. If you have aging eyes, you may need more power, but if you have good vision, and are still fairly young then i would stick to around 10. I'm wanting to get my 10x scope upgraded to max out at 14-18 just for a little extra for my long range shots. I can still hold good groups at 700 yards with 10x, but I want just a little more for the 1000+ yard shots.
I would say 4.5-14x is in the range of ideal IMO. I dial down as low as possible when hunting so I don't have to dial down when the shot opportunity presents itself. If it's the type of shot that requires more magnification, you usually have more time to dial up to make it.
Branden