I will soon receive 2 new M4 A3 uppers with this flip up front sight...



Is there a "slot" rear BUIS ( LIKE THIS ='= ) ?  My vision isn't what it used to be and I really can't stand the round hole.

The round hole might work better with these front sights, but I like setting the target on a "table".

The only one I know of was made by meprolight, and had tritium vials on either side as part of a set of night sights. I checked Brownell's, and they only list mepro's with a rear aperture now, so the notch may be discontinued.

Yer talking about a notch rear sight like on an AK?  You'd have to mount that well forward, where the AR15/M16 mounts its peep rear sight is too close for a notch rear sight, because it'll be but a blur at that distance.  I've seen some rear sights like that mounted in front of optics, as I recall it's not well received by most people because it reduces the sight radius.
Go here to see for yourself
I daresay it may be faster in acquisition, but at the expense of sight radius and precision.

Quoted: I daresay it may be faster in acquisition, but at the expense of sight radius and precision.

Thanks.  After looking at the sight picture of these hooded flip up front sights I'm getting, I think your are dead on.  Concentric circles seem much better than the "pitch fork FSB".

ZARDOZ

Cool member name!!   "THE GUN IS GOOD"

You'd have to mount that well forward, where the AR15/M16 mounts its peep rear sight is too close for a notch rear sight, because it'll be but a blur at that distance

!@%&$%...can't believe I forgot this point. There's a very good reason that all rifles that come with a notch rear sight have them mounted out in front of the receiver.

Cool member name!! "THE GUN IS GOOD"

LOL, thanks...and yes, the gun is good, ain't it?

The early all milled Thompson SMGs have a notch sight and a very eleborate (and ambitious) peep sight that goes all the way out to 600yds, for a .45 APC subgun whose effective range is 50M... .  The notch sight is pretty god dang useless when it's mounted so close to the eye