Red dot moving

[MSC]

I have a red dot  scope ( sight mark ) that i haven't used in a while, tonight i decided to mount it on my 10/22. i turned it on & looked thru it & i noticed that every time i moved my head the dot moved, i'm pretty sure that it shouldn't do this. how can you sight in something when the dot is moving?

[anweis]

What you see there is an optical artefact or an optical illusion inherent in most red-dot sights. The only way around this is to always keep your head and eyes in the same way, so that your aiming is consistent. Or, you could mount the sight far forward on the firearm and aim with both eyes, that does help both with aiming and with accuracy. 
In the more expensive red dot sights, like the Aimpoints, as you say, the red dot does not appear to move if you move your head.

[MSC]

this is actually a holographic sight, would that make any differance?

[Graybeard]

The way the makers say they work is that where ever the dot is once sighted in is where the bullet is going. They are parallax free so dot movement doesn't mean impact shift. I've not tried to verify this but it is what all the folks selling them say.

[blind ear]

I don't know but you might lock the gun in a shooting vice, 22cal probabably best, and fire it. With the gun in the vice, get the dot centered on the impact then move your eye and see if the impact moves with the dot? Will any degree of variance put you off vital zone (marked on target) at the range you will shoot?

I have heard this discussed several times but never heard a final answer. Depends on size of target and the distance it seamed. the quality of the site had a lot to do with it. good luck, eddie