What is the purpose of the "U" Notch rear sight?

[Mitchell, Esq.]

When people talk about sight alighment, they are talking about the top of the front and rear sights being equal height, with equal light on either side of the front sight.

Emphsis in marksmanship, to my understanding, is focus on the front sight in relation to everything else - target and rear sight.

This means the operable portion of the sights - front sight and rear sight - is the top, not the bottom of the sights.

So.

What does a U notch, as used in the HD sight or Warren Tactical, do that a squared shape as used in the standard square cut rear sight configuration does not?

[joshs]

As you pointed out, the bottom corners don't add anything to sight alignment, so the idea is to eliminate the right angles that may draw you eye away from the front sight. Without the sharp corners, it is supposed to be easier to look through the rear sight and focus only on the front sight.

[MEH]

It makes it easier to "align" front sights that have a "dot" (be they fiber or tritium or painted). The eye can naturally align the dot in the curved notch. I like a "U" notch rear with fiber/tritium front sights but would rather have a square notch with a black front sight.

[41magfan]

Personally, I find the U-notch offers something of a contrast to the critical square angles of sight alignment. It's not a game changer by any stretch, but I find it easier to focus on the "four corners" with such an arrangement.

I made this Heinie Straight-8 into a U-notch with a round file.

http://img252.imageshack.us/img252/7325/pict0483p.jpg (http://imageshack.us/photo/my-images/252/pict0483p.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

[CCT125US]

Personally, I find the U-notch offers something of a contrast to the critical square angles of sight alignment. It's not a game changer by any stretch, but I find it easier to focus on the "four corners" with such an arrangement.

I made this Heinie Straight-8 into a U-notch with a round file.

http://img252.imageshack.us/img252/7325/pict0483p.jpg (http://imageshack.us/photo/my-images/252/pict0483p.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

I like the look of those... my Heinie S8Q have the rear notch slightly off set to the right, this may be enough reason to make an adjustment.