So I have revised my thoughts on the A2 yet again as it pertains to practical or defensive shooting at extended distances. I stay awake at night reading and learning and studying marksmanship and the AR15 platform. Its just what I do.

Recently I posted an article about defensive iron sights and how I like 6 o'clock holds. At that time, I had not integrated longer range defensive shooting with the maximum point blank method of sighting in a rifle.

The MPBR is a method of sighting where we adjust our sights to keep the bullet floating for the longest time into a defined vitals zone.

Two defined vital zones on a human target are the head being roughly 9 inches tall, and the upper torso being roughly 18 to 20 inches tall.

My thoughts are: we can reach out to a man sized target with two sight settings. Another goal with iron sights would be NEVER to obscure the target with the irons hence I continue my 6 o'clock holds / methodology.

Our holds will be 6 o'clock under the head and just below COM for our first zero, and 6 o'clock under the torso for our second zero.

Again, we want that bullet to rise and fall within our man sized target for the longest time possible as this directly translates to how far the target is from us where the bullet still intersects the target.

So: A2 sight 8/3 + 2 clicks gives us around 8 inches of bullet rise at the apex of bullet flight for an effective zero of 366 yards. Putting the front sight at the midline of the torso will give us hits in the vitals out to 350-360 yards. Putting the front sight just below the jaw line will permit hits to the head to the same distances.

Suppose the target is further out at 400 yards or so... Well either hold will still get hits. The hold to the neckline will drop rounds on to the upper torso and the midline hold will drop rounds to the pelvic region.

Setting 2 is a pure 6 o'clock hold to the torso at the belt line of the target. This translates to 8/3 + 5 clicks. This will throw the round into the torso at all distances as the apex is never past 16 inches high and this should be used with a belt line hold. At 500 a hold to the belt line will drop an additional 6 inches into the pelvic region / upper thighs. At this point raising to a centerline hold would bring the round back into the lower abdomen.

20 inch barrel, M193, 59 degrees F, 3250 fps velocity.

I tightened the maximum height of the projectile trajectory to stay inside the 9 inch head and 18 inch torso with some wiggle room hence the 8 inch bullet rise from the first setting and 16 for the second setting.

Both of these settings, statiscally speaking, allow the projectile the largest margin for error by keeping it in flight for the longest time while intersecting the target.

YMMV

Knife_Sniper, there was a Thread last year called:  Revised Battle Sight Zero for the A2

And I think it contained something like you describe.  I searched for it, but could not find it..

How often to do expect to be shooting at man sized targets at those ranges with iron sights?

It seems to me that the majority of fighting using iron sights tends to be much closer range as target identification becomes an issue.

Most likely to happen? House distance self defense. Sure.

Does that stop me from wanting to master my rifle from point blank to the edge of 5.56s capability? No.

Can we get a link to your other thread?

That's all fine and good if your target is standing up like a tree waiting to get blasted.  

Plus you said you never want to obscure your target, yet you are doing just that at times.  

I like cutting the bull in half.  POA is POI.  And then just knowing my dope.  Seems more simple.  Although I think what you're trying to do is move the wheels less.  Which makes sense.

I *am* trying to move the wheels less, but this is a "rough draft" so I have to go to the range to try it out.

My goal is to explore maximum point blank range with the AR15 in order to maximize the time the bullet intersects the target. Since I cannot shoot at unknown distances to practice on the fly range estimation, the challenge is to make the fact that I am shooting 100-200-300-400 yards as irrelevant as possible. I want to find several zeros that cover as much ground as possible through overlap.

Whats the smallest thing I will shoot at closer ranges? A headshot. Whats the smallest thing  would be shooting at extended ranges? Body shots. I couldn't see anything smaller than a full size target at 300 + yards.

What my end goal is to try the newer 69 grain sierra tipped matchking which will impart a even flatter trajectory than what we have now.

coldblue, that page, about say's it all.

350 Meters = 385 Yards, which equals 1155 Feet (rough conversion, but close).

That's only 165 Ft short of a 1/4 Mile.  I have shot longer ranges then that with open sights, but then I'd use the Elevation Wheel, as I've found they do work.

Man SS109 is a laser out to 350 meters. Do you mind if I save that chart for demonstration on my blog?

I have been thinking about some of your comments and suggestions, so I tightened up the MPBR to 8 inches total rise and fall with a dead hold, and I will work on a 6 o'clock hold at 400+ yards.

Here is another interesting chart: maximum point blank range of different calibers and barrel lengths. Made it myself... since we are sharing and all.

I tightened up to an 8 inch vital zone which is the same size as the -0 ring on an IDPA silhouette so the chart shows a +4 -4 rise and drop with a dead hold.

This is what I do for fun in my spare time.

Kind of sounds like you're trying to re-invent the wheel...

Just remember:

There's no substitute for regular practice. If you don't use it - You will lose it.
The sights are there for a reason & when used as designed - work just fine.
Know your target & it's back-stop. If you can't clearly identify it & what's behind it, then you have no business shooting at it.
Snap-shots are for cameras & area-effect weapons - for everything else, there's Marksmanship.

I discovered long ago that the near perfect battle zero, for almost any caliber, is +3" POI at 100 yards (this works for 5.56, 7.62x39, .308, 30 carbine, etc).  

It gives you the best of all worlds.  Long effective battle zero with high and low extremes that are not too variable.  Similar to the 36 / 300 YARD (not meter) zero demonstrated in the below video.

If you like to study zeros, like I do, then you should find the following video interesting.

https://www.youtube.com/watch?v=g9oXGT55cV8