I have been, and still am, an Elcan Specter advocate. I also recently purchased a TA01 ACOG. Both optics have, what I would call, "obtuse" back-up iron sights on top of them. I was always fond of the idea on the Specter, as it seems like value-added, and I don't care for the bulk of offset irons. I recently made mention of the irons atop the Specter coming in handy in aligning with a target before dropping down into the magnified FOV. In the context of the ACOG specifically though, because it lacks a 1x optical function, I wondered about the fixed sights' viability in a CQB application. I shot a lateral transition drill with the irons on top of the Specter yesterday; the results were not very usable, as it turned out the sights needed a bit of adjustment; the majority of my shots missed to the right of the bullseye. I did note a slight reduction in time though.

My question is this: what is the primary intent of these sights? Are they a BUIS, for if the optical portion fails or is unusable? This is what Elcan implies, in their literature. Is it intended as a CQB option for optics like the ACOG, that lack an unmagnified setting? The viability as a CQB option seems limited to me. Ultimately, I'll use them however they come in handy for me, but I am curious what the original intent may have been, from an initial design perspective.

Not being a company insider, I have no way of knowing what the “intent” of such a feature was, but I am a little cynical about how manufacturers decide to include it on a sight like that. Many people are impressed by the thought of a feature rather than having any clear understanding of how useful it may actually be, and that can affect decisions about offering it. The decisions can be a sincere, “Oh, yeah: This could really be important,” “This is something our customers are going to want and be impressed with even though we know it’s pretty worthless,” or something in between.

The irons on top of an ACOG are true last-ditch "backup sights" if something were to go drastically wrong with the optic portion and it becomes totally inoperable.

They're not intended to be primary CQB sights. Read up on the "Bindon aiming concept"... That's how the ACOG is intended to be used in CQB, despite it lacking a 1x magnification option. The illuminated reticle is viewed with the right eye while the target is viewed with the left eye, and the mind overlays the illuminated reticle on top of the left eye's unmagnified target view, ignoring any magnified view in the right eye.

It takes a little bit of practice to master, but it does work. It's easier to master if you put a cap or some tape over the front of the ACOG while initially practicing with Bindon, so you're seeing the target with your left eye and the reticle on a black background with your right eye.

I am familiar with the Bindon and OEG concepts, and have employed both.

It seems that extreme conditions and optical failure are the primary motivators for the inclusion of these sights.

I see it as a good alternative to offset irons, and they also serve as an instantly available BUIS, not requiring optic removal.

Another very practical application of these sights is aiming while wearing a gas mask.