Re: 16x or 20x for shots on deer size game up to 600yards??
I've gotta agree with ol mike. You may go a long time without ever cranking up to twenty, but when that one time comes along where you need twenty it's real nice to have. As for the low end, there just isn't that much difference between 4 and 5.
Ignorance can be treated with education, sadly there is no cure for stupidity.