Originally Posted by Schumania
Looking for assistance on how I go about removing the front sight on my AR-15. Want to mount a scope on upper receiver, (dont want paralex problem) and also need to install BUIS.
I think you are on the wrong track here. I would advise against removing the front sight post.
TWO FACTORS WHICH CAUSE AND DETERMINE THE AMOUNT OF PARALLAX IN A RIFLESCOPE:
1. The distance of the target to the objective--The objective lens forms a primary image of the subject being viewed and subsequent components invert the image, and there is no parallax. The actual position at which the image is formed is dependent on the distance the target is from the objective. Closer targets are formed farther away from the objective and farther targets are formed closer to the objective. Since the reticle is in a fixed position within the scope housing, the image is not always formed in the same plane as the reticle and, hence parallax.
2. The distance the eye can move from the optical axis of the scope, is determined by exit pupil size. There is no parallax, at any distance, as long as the eye is lined up exactly with the optical axis of the scope. An exit pupil small enough to do this would be impractical. It is important to know that in every scope, there is some parallax. It is also important to know that in every scope, there is some one shooting distance at which there is no parallax. In most rifle scopes this one point of zero parallax is usually placed at a suitable mid-range point in the scopes' focal range.
In lower-quality scopes, there are other sources of parallax. If the reticle is not precisely placed the correct distance from the objective, the distance of no parallax will be exaggerated. Reticles that are not securely mounted and allowed to move even a few thousandths of an inch, will always have changing amounts of parallax. Parallax is also caused by optical deficiencies in the objective, either by design or manufacture. If spherical or astigmatic aberrations have not been corrected, images will form a considerable distance from the reticle. If you see a scope in which the apparent movement of the reticle compared with the image viewed is different from when you move your eye up and down than when you mover your eye side to side, it is because of a bad objective. No adjustment of the scope will eliminate these faults or optical deficiencies.You can check the parallax of any scope by sighting an object at normal shooting distance (not indoors), by moving your eye side to side (then up and down), as far as you can, keeping the sighted object within the field of view. The apparent movement of the reticle in relation the target is parallax
With the A2 stock, you will need some type of riser or raised weaver ring to obtain an acceptable cheek weld. The fron sight post will not be visible thru 4X and up.
If you co-witness with BUIS, you are guaranteed to use either a see through riser or see through rings.