EOtech AR-15 mounting questions / adjusting

[Planetar]

Hello all,

So far I have been shooting my AR-15 Bushmaster 16in carbine with iron sights, but I recently purchased EOTech and have been experimenting with different mounting options.

I have tried it directly on Bushmaster flat top, then with a riser, and then mounting it on carry handle with A.R.M.S adapter.

So far the option with a riser and the carry handle one seems best so far. I like the sight to be slightly higher than usual.

Few questions regarding this setup:

Is there any disadvantage why I shouldnt use carry handle mount?

Obviously the sight is higher than barrel line, so how should I adjust / zero the EoTech and on what range?

I am right handed but my right eye is currently out of function. Is there any disadvantage for very slightly tilting the rifle to left and shooting with left eye on such setup?

I realize question may be silly / fuzzy, but shooting with optics is somewhat new experience to me.

Thanks in advance folks,

 

[rcmodel]

The main disadvantage to a very high mounted sight is the bullet path has to climb a long way before it gets up to the line of sight. This makes hitting very small things at close range difficult.

The good thing is, this high line of sight extends your point-blank-range quite a ways further at long range.

In other words, the bullet path starts out below, then crosses, then drops below the line of sight again at longer range.
The higher the sight, the further out it crosses the LOS the first time.

Canting a rifle to the side is bad, for the reason above.
Instead of the bullet path raising up to the line of sight to zero, then dropping back down below the line of sight at long range, the bullet goes off to the side away from the line of sight, and the further it goes, the further away from the LOS it gets.
For long-range accuracy, the rifle must be perfectly vertical when the bullet leaves the barrel.

Another disadvantage to a high mounted optic is you cannot get a good cheek-weld on the comb of the stock to position your eye in the same place every time.
Your head has to be held up off the stock to see through the sight, with your eye bobbing around on your limber neck.

As far as zero, I would zero the rifle to hit POA at 200 yards. That will put the bullet path close enough for hits anywhere from the muzzle out to 250 - 300 yards without having to hold over.

Links to EO sighting-in targets:
http://www.eotech-inc.com/documents/M16A4-M4MWS_EOTech_Live_Fire_Target.pdf

http://www.eotech-inc.com/documents/M16A4-M4MWS_EOTech_LBS_Target.pdf

rcmodel