I read an article about zeroing 223 round.

From my understanding the 223 (if zeroed at 100 m) will never rise above line of sight. Is this only valid to some specific ammo bran d and AR15 plaatforms or is this fir all 223 and other weapons in 223 as well?

Your question is a little difficult to understand but I think what your saying is if you zero your AR15 at 100 yards will it always shoot in the same spot with different brands of ammo.

The answer is no.

It will be close. I am gonna go out on a limb and assume your just target practicing with varied ammo @ 100 yards and it will be unlikely you will see too much of a shift from your original zero at 100 yards.

Ok let me put it this way...the 223 caliber when zeroed @ say 50 m is still rising and pass the line of sight once again at X distance.

But when zeroed @ 100 m, is the bullet still rising like the 50 m zero? Hence, will pass line of sight once again in X distance just like the 50 m zero.

I'm basically looking for a zero where it meets line of sight only once. From my understanding the 100 m zero does that, but want to know if there is a general consensus about it or if it was just that one guy's observation/opinion.

"I think" I understand what your saying... and I think you want to check this PDF out. It will explain the rise and fall points of the different zeros from an AR15.

I am assuming your asking a very simple question, but your answer is yes and no. In all technicality the 100 yard zero is dropping off while the 50 yard zero at the 100 yard mark will rise for about another 50 yard and then start to drop.

Pg 35 should answer your question. Pg 39 and 40 in a visual 3D rise and fall diagram for the 50 and 100 yd bullet zeros.

http://gunwebsites.net/wp-content/uploads/2011/09/Guns-AR15-Zero-Introduction.pdf

Here is a video to go with the PDF.

http://www.youtube.com/watch?v=Klvve0ZG_jo

On a side note and this is my personal opinion. Stick with the 50 yard zero.
It is technically the easiest to deal with when it comes to not having to guess the distance of things 12in in diameter at the smallest or larger, like the human kind.

Great links thx a lot:-)