Zeroing can be confusing to explain sometimes but I just watched this video from Vigilance Elite that was SUPER simple to understand. He is using a 36 yard Zero to get the tightest groups possible at different ranges when using the same point of aim. He compares the various points of impact when using 25, 36, 50 and 100 yard zeros. Very helpful to see them all side by side. He's using .556 from an AR but I'm wondering if there is a similar sweet spot Zero for .308 out to 500-600 yards.

I think what you are alluding to is the Point Blank Range (or Maximum Point Blank Range) (link).  It is determined by your ammunition ballistic characteristics, ambient atmospheric conditions, and the size of your target - calculator.  Plug in your ballistic information and atmospheric conditions...  then pick a target size to see the point blank range.  The calculator also gives you some other interesting information - near zero, far zero, etc...  To get a PBR out to 500 yards for a .308 win, you will need a relatively large target - ~30 inch diameter (~15 inch radius)...

Yeah, it's battlesight zero.  It's not new.  The Army manual for the ACOG recommends 33m zeroing.

I knew it wasnt new. I just liked how he was able to explain it clearly for the lay person.

I try to explain this to some people, but they insist on walking out to 100y and placing a target, then burning up a whole box of ammo trying to get on paper.

"Who zeros at 36 yards? I want to shoot a lot further than that!"

The problem with close-in zeroing is the groups are tight and when they look “close enough” to POA you call it good. But then if you shoot a group at 200 or 300 suddenly you see your 36 yard group was just stroking you off.

No need to burn ammo. You can eyeball-bore-sight and be on paper with the first shot.

If you want an excellent battlefield zero, do your sight-in at the greater of the 2 distances.

Informative video with a nice illustration of the spread at certain distances with a given zero.

The logic is pretty good, and works for a lot of people.  I can't dis it; but will say in my opinion this is rather tailored for standing humans in open field calibration; and less so for many practical civilian usage - or at least, for my usage that is.

Personally I prefer a 200 yard zero (or about a 60 yard zero, though a 50 yard zero is close), as I want a tighter span of impact in that 35-250 yard zone, then you can get with a 36 yard zero.  If you look at the 4:31 spot in the video; the question is are you OK with that much span a 36 yard zero gives at a 150 yard shot?  Look at the 200 yard zero, and consider that usage going out to about 250 yards.  It's a lot tighter.

For non-military types; you're really going to be shooting at things like coyote's, hogs, gongs, armadillos, and maybe deer.  That much deviation from where you are aiming is starting to get expensive; and can be the difference between successful hit-drop, and not.  If you're shooting at a 2 MOA gong or smaller game animal at 150 yards; you're going to overshoot and miss with a 36 yard zero.  

But for more general coarse snap engagement at targets with more vertical real-estate and you're OK with that big of a span (which is a valid answer, everyone's usage and intent is different), then the biggest practical problem with the 36 yard zero is that seemingly small deviations from being exactly zero'd at 36 yards, get translated into pretty big differences once you start getting out past even just 100 yards.  So if you do zero for 36 yards, my advise is to take extra care to be as close to exactly zero'd as you possibly can, at that distance.