A buudy of mine picked up a AR upper type 50 for SHTF and asked me what I would recommended for a "set it and forget it" type zero?

I recommended 9 inches high at 100yds to be good for anti-material purposes out to 500yds.

Curious what the hive mind thinks.

The ballistics aren't much different than a 308 for practical purposes. Theres going to be a 3-4' swing between 0-500.

Anybody ought to be able to memorize the hunting holdovers for 223/308/50. I'd recommending taping a chart to the stock.

This is good info and a good rule to live by.

A bullet drop chart taped to the rifle is easy, and one less thing to think about when shooting distance shots

Dupe

Can you elaborate a little on what 308 projectile/speed out of what barrel length?

Obviously that depends on what you are shooting. My point is there is no such thing as minute of pie plate for 0-500. If you look at a 68/75 gr 5.56, a 168 /175 308, and a typical BMG Ball round, they are all close enough in drop out to 500 that one could use the same holdovers and be minute of pie plate. As I said if you run the calcs it'll be 40-45" drop on the higher BC bullets , and 45-50 on the lower BC end.

You have to kinda ignore the outliers of low BC 55 GR 223 or high BC BMG AMAX

I feel like folks should "know" that bullet drop (0 at 100) might be 10-12" at 300 but 4' at 500. I don't know off hand how to work with mildots or range with a reticle but knowing the basic holdovers and turning that into MOA or Mils seems practical.

They will diverge even more from 500-1000 but you shouldn't be shooting stuff at that range if you can't accurately range it and paste a range card to your stock.

Just take a look through an ammo site. They have 100-500 drops for all their cartridges.

http://www.hornady.com/store/223-Rem-75-gr-BTHP-Match/

A gentleman and a scholar, thank you. I had always heard that 50 BMG was identical in ballistics to M2 ball 30-06.

Right now I am set zero at 100 yards with API ammo.
At  500 yards I am 3.9 feet  low but at 1000 yards I am about 25 feet low
Out to 300 I am about 11 inches low.

With this setup out to 500 yards  big trucks will be easy to hit. Passer vehicle if you hold over to the top of the roof you will hit the passenger or if you want the engine.

For personal if you hold just above top of the head you will get mid/ Lower  body strikes  with a 50 it still will still end their ability to reengage you.

Since the area I am in is Urban / suburban I do not foresee me shooting long distance and on top of that I really don't have the experience to make long shots

There is really no  best answer for everyone.
You have to look at the environment you intend to shoot
Your skill
Your equipment capabilities
the targets you intend to engage

IF you know your velocity and bullet weight (and a few other details) you can use the attached site to calculate your MOA come-ups.

http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi/

He recently opened up the defaults for us trying the "King of The 2-Mile" competition sponsored by the FCSA.
New range default is 4000 yards.

Otherwise, if zeroed at 100 yards, come up 24-26 MOA to hit at 1000 yards.

You will need a 20 minute base on your scope mount to give any reasonable use of scope elevation adjustments.

If your intention is to shot "rocks", just go have fun.
If you're serious, record your come-ups from bottom of travel of elevation knob for the different ranges you shoot.

Have FUN
Be SAFE

The "OldmanFCSA"

I have Android phone and use a ballistic app called shooter. I put in my information and it is close.