Fast question hoping for fast answer.

I've read 300 ft. is max as well as 850 ft.

What's the real deal?

It's for CCTV and I have no specs, I've just been asked to run 700 ft.

RG6 or RG59?

And is this for color or BW video ..?

I think max for RG59 is like 1200' for BW and 1500' for Color, while RG6 is like 1800' for color .. but you loose quality at those distances without an amplifier .. 700' would be fine for either cable, if you arernt happy with the quality loss though you could always add an amp.

Make sure if you do use RG6 its solid copper center and copper braid cable (Not Cable TV cable) or you could have issues down the road ..

Could you please send me some links and references as to why you prefer a copper ground braid over aluminum? such as that used in cable tv cables. Although, I know copper is a way better conductor for a ground, I was just wondering if there were other reasons.

Thank you...

Shielding. With modulated signals you don't have to worry about shielding as much. CCTV signals however are unmodulated and as such can be affected by interferance on a much greater scale.