[Blitzzz (RIP)]

I,m not sure I understanding the "why" a 25 meter or 50 meter zero unless your just talking iron sights.

A good point for range estimating is to "think" in shooting increments, ie. 50 meters or 100 meters and combining that with your known ballistic curve. It may sound confusing but it's a system I have used for well over 30 years with M118 ball. By thinking in increments I'm able to quickly Hold off from my zero to make the hit. I found this really works well with Mil Dot.
I,m not trying to create confusion, sorry if I did.

This was in response to the question of 10.5 in barrel zero thread.
I wrote the following:

I agree with 100 meters.
if you zero at 100 meters then the following:

M-193 ball = 4 inch target area out to 150 meters.

M-855 ball =4.2 inch target area out to 150 meters.

Added Info:
also if you zero the M193 ball @ 250ms you have +9.9 inch at 200ms, -15.1 at 300.

and for the M855 ball with 300 meter zero, = a +12.6 inches @ 150+
I'd do the 100 meter zero
Blitz

But in response to your question ,Yes, 200 meters would be much like a "point blank zero". Used in hunting circles it refers to the zero distance that allows the shooter to engage a "target" with out hold off. If you can achieve that with a 200 meter zero then do it. but as you stated that's a 12 inch circle at 300 meters.
You might tighten that circle at about 175 meters to around 9.5 inches.

Let us know when you do, good luck Blitz