Red Dot on AR, too low.

[CDW4ME]

Recently bought a Stag 2T AR and a Bushnell TRS-25 red dot sight.
Mounted directly to the rail the red dot is too low; I would have to remove the front and rear sight to use it.
It seems that the red dot should be at approximately the same height as the sights to achieve proper zero.
I assume I need a riser / adapter to mount the red dot higher.
Suggestions?

 

[TurtlePhish]

http://www.amazon.com/UTG-1-Inch-13...sr_1_sc_3?ie=UTF8&qid=1327031422&sr=8-3-spell

These are great for the money.

 

[BP44]

You got it, I suggest optics planet for the riser. I have the same dot and use a bushnell 1/2'' riser on it and it works for me just fine.

 

[TurtlePhish]

There are also 1/4" and 1/2" UTG risers if you look at the suggestions on the page. Only $11.95

 

[awgrizzly]

The riser is standard equipment for mounting optics to the bare rail. The rail is designed to accept the carry handle on the M16A4. The carry handle sits high for proper acquisition with cheek weld. All other optics attached need to be at least this high and a bit higher if you wish to see over the iron sights. This is normal for mounting AR15 optics.

As you've seen there are a number of riser choices on the market, or you can buy optics with extra high mounts. A quick connect rail is quite nice and versatile, albeit spendy, since it and the scope can be quickly removed and replaced. Burris makes a very nice high mount that slopes forward for long scopes or that have a long eye relief. It may pay to visit a local gun store and get a mounting system fitted for you and your gun. There are a large number of combinations of riser (usually 1/2") and mounts (low, medium, high, extra high). You need a combo that will fit your scope and work good for you.

 

[ns66]

higher mount will be easier on the neck, but wouldn't that make aim of scope and barrel too far apart? how do you zero with 2 lines a few inches apart and not parallel?

 

[briansmithwins]

The same way you do with the irons.

First thing to realize is that you really only are ever zeroed in two places, where the curved line of the bullets path crosses the straight line of you line of sight rising and where it crosses falling.

At every other point in the bullets path the bullet is going to be to high or two low. A common range to zero 5.56 rifles at is 50 yards. That keeps the POI within about 2" of POA out to 250 yards or so.

BSW

 

[helotaxi]

how do you zero with 2 lines a few inches apart and not parallel?

You're not looking directly down the bore with any type of sight which is a good thing. If the line of sight and the bore center-line were parallel, the sights would not be zeroed at any range. The line of sight and the flight path of the bullet must intersect to be able to accurately aim. The normal sights on an AR sit almost 2" above the bore line and are canted down in relation to the bore line (like all sights are).

 

[awgrizzly]

higher mount will be easier on the neck, but wouldn't that make aim of scope and barrel too far apart? how do you zero with 2 lines a few inches apart and not parallel?

A couple things here.

A gun is only zeroed in at the range you zero it to. For all other ranges you need to learn to compensate, or you can get a scope that has marks on the elevation knob for various ranges (they are bullet and caliber dependent). It is true that the AR will have a larger variance, sight to bore, at close range. That's the way it's designed.

It is not a matter of 'easier on the neck'. Because an AR has the entire firing system in line with the stock to eliminate barrel rise when shooting, the bore is lower than a conventional rifle. As a result the sights and optics must be located higher so that the sight or scope is aligned with the eye when one's cheek is pressed against the stock (cheek weld). When you establish cheek weld the sights should be closely aligned with the eye for fast and comfortable shooting. Thus the sight or optics should also not be installed too high.

KEY POINT: If you install the scope too low, you may have a very difficult time seeing through the scope because you can't comfortably get your eye low enough. That's why the sights on an M16 are so high.

Just wanted to make this clear so folks will have a head start when they attach sights and optics to AR style rifles.

 

[ns66]

thanks all
i found this thread about zeroing, crystal clear if you are interested

http://www.ar15.com/forums/t_3_18/519578_.html