The beauty of the platform of course is that it can be whatever you desire. Long range paper killer to house clearing cannon, it can meet whatever mission you need inside it's inherent limits. It is modular and adaptable.
One recent discussion I was involved in was about zero. It seems that ideas abound and opinions vary (who knew?) About this topic. The thing is, no matter how you zero your carbine you need to understand its capabilities and limits.
Some like a 100 yard zero because that is how their 30-06 is set up. Some like the old 300 yard military zero. Some like the improved battle zero. Some have no idea.
The following is my opinion and I am not disparaging yours.
The vast majority of shots with a 5.56 carbine in a combat scenario are under 200 yards. Now I know Afghanistan had plenty beyond this, but it is the exception and not the rule.
For us civilians, the chance we would need to shoot at persons beyond 200 yards in a SHTF situation is pretty slim. The vast majority would probably be well under 100 yards, most likely under 50. Now, I know I'll get a comment from someone in Montana who has a 1000 yard line of sight from his porch. You are the exception brother and should probably be using .308 or Creedmoor.
*Edited to add* I know some consider the 5.56 to be a "poodle shooter". If you are one of the magical people who can shoot your .308 as fast and as accurately as a 5.56 and believe it sucks their souls out I am absolutely good with it. The point of the post here is not to say you're wrong, it is to help the new survivalist zero their carbine in a way that helps them be effective shooters.
The military has adopted the improved battle zero and it goes like this. You zero at 50 yards (your near zero) and your shot is back dead on at around 225 or so (your far zero). This can vary with barrel length and whether 55 or 62 grain but it is close enough for what we are discussing.
The above means simply, your shots are in a 4" circle from spitting distance to about 260 yards. No holding over required, center mass hold gets good hits.
Basically in theory, you are shooting in a 4" tube out to 2.5 football fields distance with no muss or fuss, just hits. Add in the less than MOA performance of most bulk mil-spec ammo and your likely less than solid rest and this zero gets you on a paper plate or so out to 200 or a little better. This is an EXCELLENT combat ready setup. If you can shoot paper plates standing at 250 yards with your heart pounding and bullets coming back your way, you are GTG. See why opening up your circle with a farther far zero is problematic? Your mid trajectory is very high, with other factors added it can cause misses under stress.
Open up the circle to a 6" minimum and you could zero at 44 yards, be back dead on at 260 and be in the circle to 300. To me this is the max.
The problem with the old 300 yard zero that the military used to use is that you end up about 5" high at around 175 yards and to me that ends up being just too much of a varying POI for a carbine that will be used closer, rather than further. A 300 yard zero means your bullets impact in about a 9" circle from close out to 350 yards. Add in the shakes, return fire and bulk ammo and you may now be shooting in a 15" or larger circle and that is simply too big.
In my mind it is simpler to use the 50\200 and know that at 300 yards I need to hold about 1\2 mil high, about 1 mil high at 350 and about 1.5 mils high at 400. Everything inside 250-260 is a dead hold.
You may decide on something else. That's OK. Just know how it works and understand how to utilize what you decide on. The military uses the 50\200 now and it has been proven as a solid concept.
I punched in some numbers to Strelok Ballistic Calculator and got the following. It assumes M193 55 grain in a 16" barrel.
The chart can show you what we're talking about here and what your holds with a mil based reticle will be to 500 yrds.
Of course, open sights and red dot optics work with this zero as well and will allow you to shoot about as far as you can unmagnified. With a magnified optic longer shots are as simple as using your reticle for holdover.
There are a good amount of BDC reticles out there for certain loads. I don't like them myself as you are locked into one load. Again, if you like it, great. Just know how to use it.
Get out there and get this stuff figured out while you can.