When it comes to iron sights on a modern rifle it is becoming less and less apparent whether or not they are “necessary” equipment. With the reliability of modern optics and their superiority in increasing hit percentages across a wider spectrum of shooters iron sights are taking the bench.
So when setting up and prioritizing your mission specific gear and picking ancillary equipment priority. Where do iron sights go?
Does their positioning, especially in relation to the front sight, matter?
As Aaron over with Sage Dynamics demonstrates, having the sights on the rifle in a shorter useable configuration works. It will even work at a longer distance.
The iron sight question becomes about the gear priority. If you consider BUIS mission essential equipment in case of an optic failure (like I do, I run irons with everything still) then having them functionally on the rifle in the longest configuration that doesn’t interfere with your more important systems is fine. This could put your front sight post only halfway up the front rail of your gun, and that is fine. Reducing the radius will throw more discrepancy into your overall accuracy as you change the angles involved with utilizing your iron sights but it won’t make them unusable by any stretch.
The only situation in which your sight radius needs to be a critical component of your layout is if the iron sights are your primary method of target engagement. Meaning either you do not have an optic or that you are shooting in a situation, like a match, that requires iron sights.
In every defensive connotation, having a set of iron sights you are able to bring up if needed and that are zeroed because you check them is more important than whether or not the sight radius is 11″ or 13″.
I use them. I think you should too. Dust them off and shoot with them every once in awhile, I did last weekend. Layers of redundancy on something as critical as aiming are a safe bet.